> [!PerSessionDSL] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_lwlock_parallel_hub.png"></td><td><b>Wait Category</b></td><td>LWLock</td></tr><tr><td><b>Mechanism</b></td><td><code>DSMLock</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Table/SeqScan">SeqScan</a>, <a href="Operations/ResultSet/HashJoin">HashJoin</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">Contention on the <b>Session-Level Memory Management Layer</b>. When a parallel query starts, the leader allocates a set of "Dynamic Shared Memory" segments to hold plan information, worker states, and intermediate results.</td></tr></table>