InnoDB INFORMATION_SCHEMA Buffer Pool Tables Table Overview • INNODB_BUFFER_PAGE : Holds information about each page in the  InnoDB  buffer pool. • INNODB_BUFFER_PAGE_LRU : Holds information about the pages in the  InnoDB  buffer pool, in particular how they are ordered in the LRU list that determines which pages to evict from the buffer pool when it becomes full. The  INNODB_BUFFER_PAGE_LRU  table has the same columns as the  INNODB_BUFFER_PAGE  table, except that the  INNODB_BUFFER_PAGE_LRU  table has an LRU_POSITION  column instead of a  BLOCK_ID  column. • INNODB_BUFFER_POOL_STATS : Provides buffer pool status information. Much of the same information is provided by  SHOW ENGINE INNODB STATUS  output, or may be obtained using  InnoDB  buffer pool server status variables. mysql>  SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE WHERE TABLE_NAME IS NULL OR (INSTR(TABLE_NAME, ’/’) = 0 AND INSTR(TABLE_NAME, ’.’) = 0); +----------+ | COUNT(*) | +----------+ | 1516 | +----------+ mysql>  SELECT (SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE WHERE TABLE_NAME IS NULL OR (INSTR(TABLE_NAME, ’/’) = 0 AND INSTR(TABLE_NAME, ’.’) = 0) ) AS system_pages, ( SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE ) AS total_pages, ( SELECT ROUND((system_pages/total_pages) * 100) ) AS system_page_percentage; +--------------+-------------+------------------------+ | system_pages | total_pages | system_page_percentage | +--------------+-------------+------------------------+ | 295 | 8192 | 4 | +--------------+-------------+------------------------+ mysql>  SELECT DISTINCT PAGE_TYPE FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE WHERE TABLE_NAME IS NULL OR (INSTR(TABLE_NAME, ’/’) = 0 AND INSTR(TABLE_NAME, ’.’) = 0); 3317 The type of system data in the buffer pool can be determined by querying the  PAGE_TYPE  value. For example, the following query returns eight distinct  PAGE_TYPE  values among the pages that contain system data: This query returns the approximate number of pages that contain system data, the total number of buffer pool pages, and an approximate percentage of pages that contain system data. This query provides an approximate count of pages that contain system data by excluding pages where the TABLE_NAME  value is either  NULL  or includes a slash  /  or period  .  in the table name, which indicates a user-defined table. Example 15.6 Querying System Data in the INNODB_BUFFER_PAGE Table Warning Querying the  INNODB_BUFFER_PAGE  or  INNODB_BUFFER_PAGE_LRU  table can affect performance. Do not query these tables on a production system unless you are aware of the performance impact and have determined it to be acceptable. To avoid impacting performance on a production system, reproduce the issue you want to investigate and query buffer pool statistics on a test instance.