What does KBR mean in UNCLASSIFIED

A Key Buffer Record (KBR) is a data structure used in MySQL to cache frequently accessed data in memory. It stores the key and a pointer to the corresponding data block on disk. By storing frequently accessed data in memory, KBRs can significantly improve database performance by reducing the number of disk accesses required to retrieve data.

KBRs are used in MySQL's buffer pool, which is a memory area that stores frequently accessed data blocks. When a query is executed, MySQL checks the buffer pool for the required data. If the data is found in the buffer pool, it is retrieved directly from memory. If the data is not found in the buffer pool, MySQL reads the data from disk and stores it in a KBR in the buffer pool. This process ensures that frequently accessed data is cached in memory for faster retrieval.

Using KBRs provides several benefits, including:

• Reduced disk access: By caching frequently accessed data in memory, KBRs reduce the number of disk accesses required to retrieve data, which can significantly improve database performance.
• Faster data retrieval: Data stored in KBRs can be retrieved directly from memory, which is much faster than reading data from disk.
• Improved concurrency: KBRs help improve concurrency by reducing the number of times data is read from disk, which can free up disk I/O resources for other processes.
• Reduced memory usage: KBRs only store the key and a pointer to the data block, which is more efficient than storing the entire data block in memory.

To tune KBRs for optimal performance, you can adjust the following parameters in MySQL's configuration file:

• innodb_buffer_pool_size: This parameter sets the size of the buffer pool. Increasing this value can improve performance by allowing more KBRs to be cached in memory.
• innodb_lru_scan_depth: This parameter controls how aggressively MySQL scans the buffer pool for unused KBRs. A higher value can improve performance by reducing the number of unnecessary scans.
• innodb_lru_invalidate: This parameter determines how often MySQL invalidates unused KBRs from the buffer pool. A higher value can reduce memory usage but may also affect performance.