> [!TwophaseFileSync] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_io_twophasefilesync.png"></td><td><b>Wait Category</b></td><td>IO</td></tr><tr><td><b>Mechanism</b></td><td><code>pg_twophase</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>Prepared State Durability Barrier</b>. For a two-phase commit to be reliable across a cluster, the primary must guarantee that the "Prepared" state is permanent before acknowledging the first phase of the commit to the application.</td></tr></table>