> [!NOTE] ![[assets/wl_lwlock_xlogbuffer.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | LWLock | > | **Mechanism** | `XLogBufferLock` | > | **Operations** | [[Operations/Tuple/ModifyTable]], [[Operations/Distributed/Redistribute]] | > | **Resources** | [[Resources/RAM|Memory]], [[Resources/CPU|CPU]] | > > Contention on the **Transaction Log Caching Layer**. To improve performance, Postgres does not write WAL directly to disk; instead, it writes to an in-memory ring buffer (WAL Buffers).