The buffer pool caches data pages in memory. Proper sizing is critical for database performance.
How it works:
- Data pages loaded from disk into buffer pool
- Frequently accessed pages stay in memory
- LRU or clock algorithm manages eviction
Sizing guidelines:
- Dedicated DB server: -% of RAM
- Shared server: -% of RAM
- Monitor hit ratio (should be >%)
Low hit ratio means too much disk I/O. Increase buffer pool or add indexes to reduce working set.