The INFORMATION_SCHEMA INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables Notes 26.4.7 The INFORMATION_SCHEMA INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables •Use these tables to measure the effectiveness of  InnoDB  table compression in your database. •You must have the  PROCESS  privilege to query this table. •Use the  INFORMATION_SCHEMA COLUMNS  table or the  SHOW COLUMNS  statement to view additional information about the columns of this table, including data types and default values. •For usage information, see Section 15.9.1.4, “Monitoring InnoDB Table Compression at Runtime”  and Section 15.15.1.3, “Using the Compression Information Schema Tables” . For general information about InnoDB  table compression, see Section 15.9, “InnoDB Table and Page Compression” . The  INNODB_CMPMEM  and  INNODB_CMPMEM_RESET  tables provide status information on compressed pages within the  InnoDB  buffer pool. The  INNODB_CMPMEM  and  INNODB_CMPMEM_RESET  tables have these columns: The block size in bytes. Each record of this table describes blocks of this size. A unique identifier for the buffer pool instance. The number of blocks of size  PAGE_SIZE  that are currently in use. The number of blocks of size  PAGE_SIZE  that are currently available for allocation. This column shows the external fragmentation in the memory pool. Ideally, these numbers should be at most 1. The number of times a block of size  PAGE_SIZE  has been relocated. The buddy system can relocate the allocated “buddy neighbor”  of a freed block when it tries to form a bigger freed block. Reading from the INNODB_CMPMEM_RESET  table resets this count. • PAGE_SIZE • BUFFER_POOL_INSTANCE • PAGES_USED • PAGES_FREE • RELOCATION_OPS 4854  uncompress_ops: 0 uncompress_time: 0 *************************** 4. row *************************** page_size: 8192 compress_ops: 86955 compress_ops_ok: 81182 compress_time: 27  uncompress_ops: 26828 uncompress_time: 5 *************************** 5. row *************************** page_size: 16384 compress_ops: 0 compress_ops_ok: 0 compress_time: 0  uncompress_ops: 0 uncompress_time: 0