Manual:$wgSessionsInObjectCache/ja

詳細
セッションをオブジェクト キャッシュに格納するかどうかです.

Since 1.27.0, sessions are always stored in the object cache, and this configuration parameter becomes unuseful.

キャッシュの種類は  で設定できます. This can be useful to improve performance, or to avoid the locking behavior of PHP's default session handler, which tends to prevent multiple requests for the same user from acting concurrently.