> [!NOTE] ![[assets/wl_ipc_xidgen.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | IPC | > | **Mechanism** | `GetNewTransactionId` | > | **Operations** | [[Operations/Tuple/ModifyTable]], [[Operations/Distributed/Redistribute]] | > | **Resources** | [[Resources/CPU|CPU]], [[Resources/RAM|Memory]] | > > **Serialization Bottleneck** at the heart of the engine's transaction system. Every backend that starts a "write" transaction (INSERT, UPDATE, DELETE) must request a unique, monotonic transaction ID from a single, shared counter in memory.