Checkpoint Process (CKPT)
Making Sure Changes Are Safe ✅
🧠 What Is CKPT?
The Checkpoint Process (CKPT) coordinates with the Database Writer (DBWn) to ensure that changes made in memory are safely written to disk — marking a checkpoint in the database.
Think of CKPT as the official timekeeper, ensuring all changes up to a certain point are permanently recorded.
🔄 What CKPT Does
| Function | Description |
|---|---|
| ⏱️ Initiates Checkpoints | Triggers DBWn to write dirty buffers from memory to disk. |
| 🧾 Updates File Headers | Writes checkpoint metadata to data file headers and the control file. |
| 🚦 Tracks Memory Limits | Every 3 seconds, checks if PGA memory exceeds the PGA_AGGREGATE_LIMIT and takes action if needed. |
| ⚙️ Runs Widely | CKPT runs on database instances and Oracle ASM instances. Can be a thread or OS process. |
📌 Why Checkpoints Matter
- 🔐 Ensures data consistency between memory and disk.
- 🚀 Speeds up instance recovery by limiting how far back Oracle must look in redo logs.
- 🛠️ Supports features like fast recovery and backup consistency.
💡 DBA Tip of the Day
Keep an eye on checkpoint frequency. Too frequent? It may affect performance. Too rare? Longer recovery time. Strike the right balance using FAST_START_MTTR_TARGET or tuning redo and buffer settings.