> [!NOTE] ![[assets/wl_lwlock_persessiondsl.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | LWLock | > | **Mechanism** | `DSMLock` | > | **Operations** | [[Operations/Table/SeqScan]], [[Operations/ResultSet/HashJoin]] | > | **Resources** | [[Resources/RAM|Memory]], [[Resources/CPU|CPU]] | > > Contention on the **Session-Level Memory Management Layer**. When a parallel query starts, the leader allocates a set of "Dynamic Shared Memory" segments to hold plan information, worker states, and intermediate results.