> [!NOTE] ![[assets/wl_io_dsmfillzero.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | IO | > | **Mechanism** | `dsm_create` | > | **Operations** | [[Operations/Table/SeqScan]], [[Operations/ResultSet/HashJoin]] | > | **Resources** | [[Resources/RAM|Memory]], [[Resources/CPU|CPU]] | > > This wait event represents a **Memory Allocation Barrier**. When a parallel query starts, the leader backend must create one or more DSM segments to facilitate communication with its workers.