Improved the session handler so that it does not write unchanged sessions to database.

Author: tbrehm

interface/lib/classes/session.inc.php

@@ -56,7 +56,7 @@ function read ($session_id) {
 
         if (is_array($rec)) {
 			$this->session_array = $rec;
-			return $rec['session_data'];
+			return $this->session_array['session_data'];
 		} else {
 			return '';
 		}
@@ -68,6 +68,11 @@ function write ($session_id, $session_data) {
             $this->session_array = array();
         }
 
+		// Dont write session to DB if session data has not been changed after reading it.
+		if(isset($this->session_array['session_data']) && $this->session_array['session_data'] != '' && $this->session_array['session_data'] == $session_data) {
+			return true;
+		}
+		
 
         if ($this->session_array['session_id'] == '') {
 			$session_id   = $this->db->quote($session_id);