# 🐘 The Workload Library (Wait Events) > [!NOTE] ![[assets/wl_workloads_map.png|256]] > > This directory is the **Workload Diagnostic Library**. Every file represents a specific PostgreSQL wait event, detailing the physical mechanics, resource contention, and query operations involved. > > | Category | Description | > | :--- | :--- | > | **Activity** | The engine is waiting for a background process to finish a task. | > | **BufferPin** | A worker is waiting to access a data page being held by another process. | > | **Client** | The engine is waiting for the user or application to send data or acknowledge. | > | **IO** | Physical disk operations (Read, Write, Sync, Extend). | > | **IPC** | Inter-Process Communication and coordination (Shared Memory, Queues). | > | **Lock** | Heavyweight relational locks (Table, Row, Page). | > | **LWLock** | Lightweight shared-memory locks (Buffer Mapping, WAL, etc). | > | **Timeout** | Intentional sleeps and throttle delays. | For the complete architectural mapping of wait events, see the [[Manuscript/07 - Wait Events & Concurrency/7.1 - Wait Events (The Relay Race)|Chapter 7.1 Wait Events]].