> [!ProcArrayGroupUpdate] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_ipc_procarraygroupupdate.png"></td><td><b>Wait Category</b></td><td>IPC</td></tr><tr><td><b>Mechanism</b></td><td><code>ProcArrayGroupClearXid</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Tuple/ModifyTable">ModifyTable</a>, <a href="Operations/Table/SeqScan">SeqScan</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/CPU">CPU</a>, <a href="Resources/RAM">Memory</a></td></tr><tr><td colspan="3">Optimization of the <b>Visibility Bookkeeping</b> system. The <code>ProcArray</code> is a shared memory structure that tracks all active XIDs; clearing an XID from this array is a required step for a transaction to be considered "fully finished" and visible to other queries.</td></tr></table>