> [!transactionid] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_lock_transactionid.png"></td><td><b>Wait Category</b></td><td>Lock</td></tr><tr><td><b>Mechanism</b></td><td><code>XactLockTableWait</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">This wait event is the definitive marker of <b>Row-Level Contention</b>. When two transactions attempt to modify the same row (tuple), the second transaction must stall until the first one either commits or rolls back.</td></tr></table>