Index: admin_config.php
===================================================================
--- admin_config.php	(revision 14636)
+++ admin_config.php	(working copy)
@@ -24,6 +24,10 @@
 			1 => 'event',
 		),
 
+		'RegularEvents' => Array(
+			'optimize_performance' => Array('EventName' => 'OnOptimizePerformance', 'RunInterval' => 86400, 'Type' => reAFTER),
+		),
+
 		'TitlePresets' => Array (
 			'tree_root'		=>	Array ('format' => '!la_section_overview!'),
 
Index: admin_events_handler.php
===================================================================
--- admin_events_handler.php	(revision 14636)
+++ admin_events_handler.php	(working copy)
@@ -1384,6 +1384,53 @@
 			$event->status = kEvent::erFAIL;
 		}
 	}
+
+	/**
+	 * 1. Delete all Debug files from system/.restricted folder	(format debug_@977827436@.txt)
+	 * 2. Run MySQL OPTIMIZE SQL one by one on all In-Portal tables (found by prefix).
+	 *
+	 * @param kEvent $event
+	 */
+	function OnOptimizePerformance(&$event)
+	{
+		$start_time = adodb_mktime();
+		$active_sessions = array_flip(
+			$this->Conn->GetCol('SELECT SessionKey
+				FROM ' . TABLE_PREFIX. 'UserSession
+				WHERE LastAccessed > ' . adodb_mktime()
+			)
+		);
+
+		$files = scandir(RESTRICTED);
+		$file_path = RESTRICTED.'/';
+		foreach ($files AS $file_name) {
+
+			if (!preg_match('#^debug_@([0-9]{9})@.txt$#', $file_name, $matches)) {
+				// not debug file
+				continue;
+			}
+
+			$sid = $matches[1];
+
+			if (isset($active_sessions[$sid])) {
+				// debug file belongs to an active session
+				continue;
+			}
+
+			if (filemtime($file_path.$file_name) > $start_time) {
+				// debug file is recently created (after sessions snapshot)
+				continue;
+			}
+
+			@unlink($file_path.$file_name);
+		}
+
+		$system_tables = $this->Conn->GetCol('SHOW TABLES LIKE "'.TABLE_PREFIX.'%"');
+
+		foreach ($system_tables AS $table_name) {
+			$this->Conn->Query('OPTIMIZE TABLE '.$table_name);
+		}
+	}
 }