How are cache buffer chains implemented in MariaDB 11?

In MariaDB 11, the cache buffer chains (CBC) implementation is part of the InnoDB storage engine. The CBC is a data structure used to manage the InnoDB buffer pool, which is a cache that stores frequently accessed data pages to reduce the number of disk I/O operations.

The CBC is a linked list of buffer frames, where each buffer frame represents a page in the buffer pool. The CBC helps to efficiently manage the buffer pool by providing an efficient way to search for pages in the buffer pool and to keep track of which pages are currently in the buffer pool.

When a page is read from disk into the buffer pool, it is added to the end of the CBC list. When a page is removed from the buffer pool, it is removed from the CBC list. The CBC also helps to implement the Least Recently Used (LRU) algorithm, which determines which pages to evict from the buffer pool when the buffer pool is full.

The CBC implementation in MariaDB 11 is optimized for fast access and provides low overhead for inserting and removing pages from the buffer pool. This helps to ensure that the buffer pool is used efficiently, reducing the number of disk I/O operations and improving the overall performance of the database system.

How to monitor cache buffer chains in MariaDB 11?

In MariaDB 11, you can monitor the cache buffer chains (CBC) in the InnoDB buffer pool by using several methods, including:

  1. The SHOW ENGINE INNODB STATUS command: This command displays the current status of the InnoDB storage engine, including information about the buffer pool, including the CBC list. The output of this command provides detailed information about the buffer pool, including the number of pages in the buffer pool, the number of pages in the CBC, and the number of buffer pool hits and misses.
  2. The Performance Schema: The Performance Schema provides a set of performance-related tables that you can query to monitor various aspects of the database system, including the buffer pool and the CBC.
  3. The innodb_buffer_pool_pages_total and innodb_buffer_pool_pages_data status variables: These variables provide information about the total number of pages in the buffer pool and the number of data pages in the buffer pool, respectively.
  4. The innodb_buffer_pool_read_requests and innodb_buffer_pool_reads status variables: These variables provide information about the number of buffer pool read requests and the number of physical disk reads, respectively.

By monitoring these metrics, you can gain insight into the performance of the InnoDB buffer pool and the CBC, and take action to optimize the buffer pool size and configuration as needed.

About Shiv Iyer 422 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.