1 files changed, 47 insertions, 35 deletions
diff --git a/phpBB/includes/functions_admin.php b/phpBB/includes/functions_admin.php
index 89892feb30..3178d35c34 100644
--- a/phpBB/includes/functions_admin.php
+++ b/phpBB/includes/functions_admin.php
@@ -1125,53 +1125,65 @@ function delete_attachments($mode, $ids, $resync = true)
 }
 
 /**
-* Remove topic shadows
+* Deletes shadow topics pointing to a specified forum.
+*
+* @param int		$forum_id		The forum id
+* @param string		$sql_more		Additional WHERE statement, e.g. t.topic_time < (time() - 1234)
+* @param bool		$auto_sync		Will call sync() if this is true
+*
+* @return array		Array with affected forums
+*
+* @author bantu
 */
-function delete_topic_shadows($max_age, $forum_id = '', $auto_sync = true)
+function delete_topic_shadows($forum_id, $sql_more = '', $auto_sync = true)
 {
-	$where = (is_array($forum_id)) ? 'AND ' . $db->sql_in_set('t.forum_id', array_map('intval', $forum_id)) : (($forum_id) ? 'AND t.forum_id = ' . (int) $forum_id : '');
+	global $db;
 
-	switch ($db->sql_layer)
+	if (!$forum_id)
 	{
-		case 'mysql4':
-		case 'mysqli':
-			$sql = 'DELETE t.*
-				FROM ' . TOPICS_TABLE . ' t, ' . TOPICS_TABLE . ' t2
-				WHERE t.topic_moved_id = t2.topic_id
-					AND t.topic_time < ' . (time() - $max_age)
-				. $where;
-			$db->sql_query($sql);
-		break;
+		// Nothing to do.
+		return;
+	}
 
-		default:
-			$sql = 'SELECT t.topic_id
-				FROM ' . TOPICS_TABLE . ' t, ' . TOPICS_TABLE . ' t2
-				WHERE t.topic_moved_id = t2.topic_id
-					AND t.topic_time < ' . (time() - $max_age)
-				. $where;
-			$result = $db->sql_query($sql);
+	// Set of affected forums we have to resync
+	$sync_forum_ids = array();
 
-			$topic_ids = array();
-			while ($row = $db->sql_fetchrow($result))
-			{
-				$topic_ids[] = $row['topic_id'];
-			}
-			$db->sql_freeresult($result);
+	// Amount of topics we select and delete at once.
+	$batch_size = 500;
 
-			if (sizeof($topic_ids))
-			{
-				$sql = 'DELETE FROM ' . TOPICS_TABLE . '
-					WHERE ' . $db->sql_in_set('topic_id', $topic_ids);
-				$db->sql_query($sql);
-			}
-		break;
+	do
+	{
+		$sql = 'SELECT t2.forum_id, t2.topic_id
+			FROM ' . TOPICS_TABLE . ' t2, ' . TOPICS_TABLE . ' t
+			WHERE t2.topic_moved_id = t.topic_id
+				AND t.forum_id = ' . (int) $forum_id . '
+				' . (($sql_more) ? 'AND ' . $sql_more : '');
+		$result = $db->sql_query_limit($sql, $batch_size);
+
+		$topic_ids = array();
+		while ($row = $db->sql_fetchrow($result))
+		{
+			$topic_ids[] = (int) $row['topic_id'];
+
+			$sync_forum_ids[(int) $row['forum_id']] = (int) $row['forum_id'];
+		}
+		$db->sql_freeresult($result);
+
+		if (!empty($topic_ids))
+		{
+			$sql = 'DELETE FROM ' . TOPICS_TABLE . '
+				WHERE ' . $db->sql_in_set('topic_id', $topic_ids);
+			$db->sql_query($sql);
+		}
 	}
+	while (sizeof($topic_ids) == $batch_size);
 
 	if ($auto_sync)
 	{
-		$where_type = ($forum_id) ? 'forum_id' : '';
-		sync('forum', $where_type, $forum_id, true, true);
+		sync('forum', 'forum_id', $sync_forum_ids, true, true);
 	}
+
+	return $sync_forum_ids;
 }
 
 /**