dbModel read resource does not implement Zend_Db_Adapter_Abstract
I've recently updated the MySQL server of my test store from 5.5 to Percona 5.6 and since then the front page and the category pages won't load fully. I checked the logs and found the following error: "dbModel read resource does not implement Zend_Db_Adapter_Abstract". I did some search and tried the methods mentioned in the posts I found. Things like clearing the cache, changing permissions for specific folders and reindexing. So far neither of these worked.