> [!NotifyQueueTailLock] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_lwlock_notify_taillock.png"></td><td><b>Wait Category</b></td><td>LWLock</td></tr><tr><td><b>Mechanism</b></td><td><code>NotifyQueueTail</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Other/FunctionScan">FunctionScan</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/RAM">Memory</a>, <a href="Resources/CPU">CPU</a></td></tr><tr><td colspan="3">Serialization stall in the <b>IPC Cleanup Layer</b>. In the <code>LISTEN/NOTIFY</code> system, messages are stored in a circular buffer. This lock is required for a backend process to advance the "tail" pointer of the queue.</td></tr></table>