ZF-6828: __sleep of Zend_Db's Adapters
__sleep() method of class Zend_Db_Adapter_* mustn't finish connection to DB ($this->_connection = false;).
Think about serialization of for example the Zend_Paginator (for caching it in other way than Zend_Paginator::setCache() do). If we'll serialize Zend_Paginator (which used Zend_Paginator_Adapter_DbSelect), we serialize Zend_Db_Adapter too. So we disconnect connection from a database. Next call to any Zend_Db_* (with lazy connection) creates new connection...