diff --git a/phpBB/phpbb/db/migration/data/v31x/add_log_time_index.php b/phpBB/phpbb/db/migration/data/v31x/add_log_time_index.php
new file mode 100644
index 0000000000..f53eedcd49
--- /dev/null
+++ b/phpBB/phpbb/db/migration/data/v31x/add_log_time_index.php
@@ -0,0 +1,46 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\migration\data\v31x;
+
+class add_log_time_index extends \phpbb\db\migration\migration
+{
+	static public function depends_on()
+	{
+		return array(
+			'\phpbb\db\migration\data\v31x\v319',
+		);
+	}
+
+	public function update_schema()
+	{
+		return array(
+			'add_index' => array(
+				$this->table_prefix . 'log' => array(
+					'log_time'	=> array('log_time'),
+				),
+			),
+		);
+	}
+
+	public function revert_schema()
+	{
+		return array(
+			'drop_keys' => array(
+				$this->table_prefix . 'log' => array(
+					'log_time',
+				),
+			),
+		);
+	}
+}