> [!ControlFileWriteUpdate] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_io_controlfilewriteupdate.png"></td><td><b>Wait Category</b></td><td>IO</td></tr><tr><td><b>Mechanism</b></td><td><code>pg_control</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Table/SeqScan">SeqScan</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/disk IO">disk IO</a>, <a href="Resources/CPU">CPU</a></td></tr><tr><td colspan="3"><b>Active State Change Bottleneck</b>. It is specifically triggered during the "Update" phase of the control file lifecycle, where the engine is modifying fields such as the <code>nextXID</code> or <code>latestCompletedXID</code>.</td></tr></table>