Fellow self-hosted WordPress bloggers, if you installed DB Cache Reloaded plugin on your wp blog, you are strongly advised not to update from WP 3.0.5 or earlier versions to WP 3.1, because, as indicated in the title, the latest WordPress 3.1 breaks DB Cache Reloaded.
The errors warning in the dashboard reads:
DB Cache Reloaded Error: wpdb class is redefined, plugin cannot work!
Previous definition is at /home/…../……com/wp-includes/wp-db.php:52.
DB Cache Reloaded Error: DB Module (wpdb class) is not loaded. Please open the Options Page, disable caching (remember to save options) and enable it again. If this will not help, please check FAQ how to do manual upgrade.
Even you go to Options Page and disable and re-enable the plugin, the errors is still there.
When check the DB Cache Reloaded page here, the plugin which was advised to be compatible with WP 3.0.9 wasn’t undated since 2010-6-21. To solve the problem, one may have to wait for its development team to release a new update.
For those who’ve already updated to WP 3.1, you either can restore your WP installation to an earlier version or have the emergency use of its Wrapper mode, though this has less performance.