ZF-47: session_commit() before header redirect (TRAC#48)
If you are writing things to the session and then call Zend_Controller_Action::_redirect() occasionally your changes to the session variables will not be saved. This is due to the fact that header redirects occasionally happen before the php saves the session to permanent storage on the server. This happens intermittently and is a vexing problem to fix.
This could easily be remedied if _redirect added a session_commit() before sending a redirection header.
The only other way to fix this is to have the developer call session_commit() every time they alter a session variable, or have them call session_write_close() before making a call to Zend_Controller_Action::_redirect(). Those are inferior solutions in my opinion because the proposed alteration to _redirect() is so simple and non-intrusive.