diff --git a/WEB-INF/config.php.dist b/WEB-INF/config.php.dist
index 6b6a68d8..b5f078d2 100644
--- a/WEB-INF/config.php.dist
+++ b/WEB-INF/config.php.dist
@@ -68,6 +68,13 @@ define('WEEKEND_START_DAY', 6);
 // define('PHP_SESSION_PATH', '/tmp/timetracker'); // Directory must exist and be writable.
 
 
+// SESSION_HANDLER
+// Set session storage.
+// 'file' : file stroage. Default value
+// 'db'   : db stroage
+define('SESSION_HANDLER', 'file');
+
+
 // LOGIN_COOKIE_NAME
 //
 // Cookie name for user login to remember it between browser sessions.
diff --git a/WEB-INF/lib/ttSession.class.php b/WEB-INF/lib/ttSession.class.php
new file mode 100644
index 00000000..06e7078e
--- /dev/null
+++ b/WEB-INF/lib/ttSession.class.php
@@ -0,0 +1,80 @@
+<?php
+
+// ttSession classe is used to store sessions in databse
+class ttSession {
+  private $id = null;   // session id
+  private $expire = 0;  // session expires
+  private $data = null; // session datas
+  private $db = null;   // db connection
+
+  // Constructor.
+  public function __construct() {
+    // Set handler to overide SESSION
+    session_set_save_handler(
+      array($this, "_open"),
+      array($this, "_close"),
+      array($this, "_read"),
+      array($this, "_write"),
+      array($this, "_destroy"),
+      array($this, "_gc")
+    );
+  }
+
+  public function _open() {
+    $this->db = getConnection();
+    $this->_gc(PHPSESSID_TTL);
+    return true;
+  }
+
+  public function _close() {
+    $this->db = null;
+    return true;
+  }
+
+  public function _read($id) {
+    $id = preg_replace('/[^a-zA-Z0-9,\-]/', '', $id);
+    $sql = "SELECT data FROM tt_sessions WHERE id = '".$id."'";
+    $res = $this->db->query($sql);
+    if (is_a($res, 'PEAR_Error')) {
+      return ""; // Return an empty string
+    }
+    $row = $res->fetchRow();
+    if (empty($row['data'])) {
+      return ""; // Return an empty string
+    }
+    else {
+      return $row['data'];
+    }
+  }
+
+  public function _write($id, $data) {
+    $id = preg_replace('/[^a-zA-Z0-9,\-]/', '', $id);
+    $expire = time(); // Create time stamp
+    $sql = "REPLACE INTO tt_sessions (id, expire, data) VALUES ('".$id."', $expire, '".$data."')";
+    $affected = $this->db->exec($sql);
+    if (is_a($affected, 'PEAR_Error')) {
+      return false;
+    }
+    return true;
+  }
+
+  public function _destroy($id) {
+    $id = preg_replace('/[^a-zA-Z0-9,\-]/', '', $id);
+    $sql = "DELETE FROM tt_sessions WHERE id = '".$id."'";
+    $affected = $this->db->exec($sql);
+    if (is_a($affected, 'PEAR_Error')) {
+      return false;
+    }
+    return true;
+  }
+
+  public function _gc($lifetime) {
+    $old = time() - intval($lifetime);
+    $sql = "DELETE FROM tt_sessions WHERE expire < $old";
+    $affected = $this->db->exec($sql);
+    if (is_a($affected, 'PEAR_Error')) {
+      return false;
+    }
+    return true;
+  }
+}
\ No newline at end of file
diff --git a/dbinstall.php b/dbinstall.php
index 44fede0c..8eba7e9b 100644
--- a/dbinstall.php
+++ b/dbinstall.php
@@ -1202,6 +1202,12 @@ function ttGenerateKeys() {
     ttExecute("UPDATE `tt_site_config` SET param_value = '1.22.3', modified = now() where param_name = 'version_db' and param_value = '1.21.7'");
   }
 
+  if (array_key_exists('convert12203to12204', $_POST)) {
+    // Feature store sessions in database
+    ttExecute("CREATE TABLE `tt_sessions` (`id` varchar(32) NOT NULL, `expire` int(10) unsigned, `data` text NOT NULL, PRIMARY KEY (`id`))");
+    ttExecute("UPDATE `tt_site_config` SET param_value = '1.22.4', modified = now() where param_name = 'version_db' and param_value = '1.22.3'");
+  }
+
   if (array_key_exists('cleanup', $_POST)) {
     $mdb2 = getConnection();
     $inactive_orgs = ttOrgHelper::getInactiveOrgs();
@@ -1220,32 +1226,33 @@ function ttGenerateKeys() {
     // ttExecute("delete from tt_custom_field_log where status is null");
     // ttExecute("delete from tt_expense_items where status is null");
 
-    ttExecute("OPTIMIZE TABLE tt_client_project_binds");
-    ttExecute("OPTIMIZE TABLE tt_clients");
-    ttExecute("OPTIMIZE TABLE tt_config");
-    ttExecute("OPTIMIZE TABLE tt_cron");
-    ttExecute("OPTIMIZE TABLE tt_timesheets");
-    ttExecute("OPTIMIZE TABLE tt_custom_field_log");
-    ttExecute("OPTIMIZE TABLE tt_custom_field_options");
-    ttExecute("OPTIMIZE TABLE tt_custom_fields");
-    ttExecute("OPTIMIZE TABLE tt_expense_items");
-    ttExecute("OPTIMIZE TABLE tt_fav_reports");
-    ttExecute("OPTIMIZE TABLE tt_invoices");
-    ttExecute("OPTIMIZE TABLE tt_log"); // This locks the production table for 4 minutes. Impossible to login, etc.
+    ttExecute("OPTIMIZE TABLE `tt_client_project_binds`");
+    ttExecute("OPTIMIZE TABLE `tt_clients`");
+    ttExecute("OPTIMIZE TABLE `tt_config`");
+    ttExecute("OPTIMIZE TABLE `tt_cron`");
+    ttExecute("OPTIMIZE TABLE `tt_timesheets`");
+    ttExecute("OPTIMIZE TABLE `tt_custom_field_log`");
+    ttExecute("OPTIMIZE TABLE `tt_custom_field_options`");
+    ttExecute("OPTIMIZE TABLE `tt_custom_fields`");
+    ttExecute("OPTIMIZE TABLE `tt_expense_items`");
+    ttExecute("OPTIMIZE TABLE `tt_fav_reports`");
+    ttExecute("OPTIMIZE TABLE `tt_invoices`");
+    ttExecute("OPTIMIZE TABLE `tt_log`"); // This locks the production table for 4 minutes. Impossible to login, etc.
                                         // TODO: what should we do about it?
-    ttExecute("OPTIMIZE TABLE tt_monthly_quotas");
-    ttExecute("OPTIMIZE TABLE tt_templates");
-    ttExecute("OPTIMIZE TABLE tt_project_template_binds");
-    ttExecute("OPTIMIZE TABLE tt_predefined_expenses");
-    ttExecute("OPTIMIZE TABLE tt_project_task_binds");
-    ttExecute("OPTIMIZE TABLE tt_projects");
-    ttExecute("OPTIMIZE TABLE tt_tasks");
-    ttExecute("OPTIMIZE TABLE tt_groups");
-    ttExecute("OPTIMIZE TABLE tt_tmp_refs");
-    ttExecute("OPTIMIZE TABLE tt_user_project_binds");
-    ttExecute("OPTIMIZE TABLE tt_users");
-    ttExecute("OPTIMIZE TABLE tt_roles");
-    ttExecute("OPTIMIZE TABLE tt_files");
+    ttExecute("OPTIMIZE TABLE `tt_monthly_quotas`");
+    ttExecute("OPTIMIZE TABLE `tt_templates`");
+    ttExecute("OPTIMIZE TABLE `tt_project_template_binds`");
+    ttExecute("OPTIMIZE TABLE `tt_predefined_expenses`");
+    ttExecute("OPTIMIZE TABLE `tt_project_task_binds`");
+    ttExecute("OPTIMIZE TABLE `tt_projects`");
+    ttExecute("OPTIMIZE TABLE `tt_tasks`");
+    ttExecute("OPTIMIZE TABLE `tt_groups`");
+    ttExecute("OPTIMIZE TABLE `tt_tmp_refs`");
+    ttExecute("OPTIMIZE TABLE `tt_user_project_binds`");
+    ttExecute("OPTIMIZE TABLE `tt_users`");
+    ttExecute("OPTIMIZE TABLE `tt_roles`");
+    ttExecute("OPTIMIZE TABLE `tt_files`");
+    ttExecute("OPTIMIZE TABLE `tt_sessions`");
   }
 
   print "Done.<br>\n";
@@ -1258,7 +1265,7 @@ function ttGenerateKeys() {
 <h2>DB Install</h2>
 <table width="80%" border="1" cellpadding="10" cellspacing="0">
   <tr>
-    <td width="80%"><b>Create database structure (v1.22.3)</b>
+    <td width="80%"><b>Create database structure (v1.22.4)</b>
     <br>(applies only to new installations, do not execute when updating)</br></td><td><input type="submit" name="crstructure" value="Create"></td>
   </tr>
 </table>
@@ -1310,6 +1317,10 @@ function ttGenerateKeys() {
     <td>Update database structure (v1.19 to v1.22.3)</td>
     <td><input type="submit" name="convert11900to12203" value="Update"></td>
   </tr>
+  <tr valign="top">
+    <td>Update database structure (v1.22.3 to v1.22.4)</td>
+    <td><input type="submit" name="convert12203to12204" value="Update"></td>
+  </tr>
 </table>
 
 <h2>DB Maintenance</h2>
diff --git a/initialize.php b/initialize.php
index 18946798..f19456a1 100644
--- a/initialize.php
+++ b/initialize.php
@@ -66,9 +66,10 @@
 // Change http cache expiration time to 1 minute.
 session_cache_expire(1);
 
-$phpsessid_ttl = defined('PHPSESSID_TTL') ? PHPSESSID_TTL : 60*60*24;
 // Set lifetime for garbage collection.
-ini_set('session.gc_maxlifetime', $phpsessid_ttl);
+if (!defined('PHPSESSID_TTL')) define('PHPSESSID_TTL', 60*60*24);
+ini_set('session.gc_maxlifetime', PHPSESSID_TTL);
+
 // Set PHP session path, if defined to avoid garbage collection interference from other scripts.
 if (defined('PHP_SESSION_PATH') && realpath(PHP_SESSION_PATH)) {
   ini_set('session.save_path', realpath(PHP_SESSION_PATH));
@@ -80,14 +81,21 @@
 if (!defined('LOGIN_COOKIE_NAME')) define('LOGIN_COOKIE_NAME', 'tt_login');
 
 // Set session cookie lifetime.
-session_set_cookie_params($phpsessid_ttl);
+session_set_cookie_params(PHPSESSID_TTL);
 if (isset($_COOKIE[SESSION_COOKIE_NAME])) {
   // Extend PHP session cookie lifetime by PHPSESSID_TTL (if defined, otherwise 24 hours) 
   // so that users don't have to re-login during this period from now. 
-  setcookie(SESSION_COOKIE_NAME, $_COOKIE[SESSION_COOKIE_NAME],  time() + $phpsessid_ttl, '/');
+  setcookie(SESSION_COOKIE_NAME, $_COOKIE[SESSION_COOKIE_NAME],  time() + PHPSESSID_TTL, '/');
+}
+
+// Set session storage
+if (!defined('SESSION_HANDLER')) define('SESSION_HANDLER', 'file');
+if (SESSION_HANDLER === 'db') {
+  import('ttSession');
+  $ttSession = new ttSession();
 }
 
-// Start or resume PHP session.
+// Start session
 session_name(SESSION_COOKIE_NAME);
 @session_start();
 
@@ -136,8 +144,13 @@
 import('ttUser');
 $user = new ttUser(null, $auth->getUserId());
 if ($user->custom_logo) {
-  $smarty->assign('custom_logo', 'img/'.$user->group_id.'.png');
-  $smarty->assign('mobile_custom_logo', '../img/'.$user->group_id.'.png');
+  if (file_exists('img/'.$user->group_id.'.png')) {
+    $smarty->assign('custom_logo', 'img/'.$user->group_id.'.png');
+    $smarty->assign('mobile_custom_logo', '../img/'.$user->group_id.'.png');
+  }
+  else {
+    $user->custom_logo = 0;
+  }
 }
 $smarty->assign('user', $user);
 
diff --git a/mysql.sql b/mysql.sql
index f614d0ac..6b9e4da6 100644
--- a/mysql.sql
+++ b/mysql.sql
@@ -623,4 +623,16 @@ CREATE TABLE `tt_site_config` (
   PRIMARY KEY  (`param_name`)
 );
 
-INSERT INTO `tt_site_config` (`param_name`, `param_value`, `created`) VALUES ('version_db', '1.22.3', now()); # TODO: change when structure changes.
+INSERT INTO `tt_site_config` (`param_name`, `param_value`, `created`) VALUES ('version_db', '1.22.4', now()); # TODO: change when structure changes.
+
+
+#
+# Structure for table tt_sessions.
+# This table stores sessions data
+#
+CREATE TABLE `tt_sessions` (
+  `id` varchar(32) NOT NULL,  # session id
+  `expire` int(10) unsigned,  # session expire
+  `data` text NOT NULL,       # session 
+  PRIMARY KEY (`id`)
+)