diff --git a/phpBB/includes/config/db.php b/phpBB/includes/config/db.php
index 1e07e1f67f..a753d12cd0 100644
--- a/phpBB/includes/config/db.php
+++ b/phpBB/includes/config/db.php
@@ -52,7 +52,11 @@ class phpbb_config_db extends phpbb_config
 				FROM ' . $this->table . '
 				WHERE is_dynamic = 1';
 			$result = $this->db->sql_query($sql);
-			$config += $this->db->sql_fetchrowset($result);
+
+			while ($row = $this->db->sql_fetchrow($result))
+			{
+				$config[$row['config_name']] = $row['config_value'];
+			}
 			$this->db->sql_freeresult($result);
 		}
 		else
diff --git a/tests/config/db_test.php b/tests/config/db_test.php
index 07f3bf8d5a..e291c05c8f 100644
--- a/tests/config/db_test.php
+++ b/tests/config/db_test.php
@@ -35,6 +35,17 @@ class phpbb_config_db_test extends phpbb_database_test_case
 		$this->assertEquals('42', $this->config['bar']);
 	}
 
+	public function test_load_cached()
+	{
+		$cache = new phpbb_mock_cache(array('config' => array('x' => 'y')));
+		$this->config = new phpbb_config_db($this->db, $cache, 'phpbb_config');
+
+		$this->assertTrue(!isset($this->config['foo']));
+		$this->assertEquals('42', $this->config['bar']);
+
+		$this->assertEquals('y', $this->config['x']);
+	}
+
 	public function test_offset_set()
 	{
 		$this->config['foo'] = 'x'; // temporary set