diff --git a/phpBB/includes/db/dbal.php b/phpBB/includes/db/dbal.php
index ed6ba71fea..b49f4511aa 100644
--- a/phpBB/includes/db/dbal.php
+++ b/phpBB/includes/db/dbal.php
@@ -588,7 +588,12 @@ class dbal
 
 			trigger_error($message, E_USER_ERROR);
 		}
-		
+
+		if ($this->transaction)
+		{
+			$this->sql_transaction('rollback');
+		}
+
 		return $error;
 	}
 
diff --git a/phpBB/install/database_update.php b/phpBB/install/database_update.php
index 3b506a55b2..03f64c8f24 100644
--- a/phpBB/install/database_update.php
+++ b/phpBB/install/database_update.php
@@ -1649,6 +1649,8 @@ $cache->purge();
 
 <?php
 
+garbage_collection();
+
 if (function_exists('exit_handler'))
 {
 	exit_handler();