> [!NOTE] ![[assets/wl_lwlock_addinshmeminit.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | LWLock | > | **Mechanism** | `AddinShmemInitLock` | > | **Operations** | [[Operations/Table/SeqScan]] | > | **Resources** | [[Resources/RAM|Memory]], [[Resources/CPU|CPU]] | > > **Extension Resource Allocation Barrier**. Many Postgres extensions (such as `pg_stat_statements` or `pgvector`) require a fixed amount of shared memory to track their internal state.