Sometimes you need to change the Magento configuration during runtime. For example this is the way to temporarily disable the category flat tables <?php Mage::app()->getCacheInstance()->banUse(‘config’); //better switch of config cache Mage::app()->getStore()->setConfig(‘catalog/frontend/flat_catalog_category’, “0”); // … Do wired stuff … Mage::app()->getStore()->setConfig(‘catalog/frontend/flat_catalog_category’, “1”); Attention: You have to reindex categories afterwards!!!