InnoDB INFORMATION_SCHEMA Tables about Compression These two tables have identical contents, but reading from  INNODB_CMP_RESET  resets the statistics on compression and uncompression operations. For example, if you archive the output of INNODB_CMP_RESET  every 60 minutes, you see the statistics for each hourly period. If you monitor the output of  INNODB_CMP  (making sure never to read  INNODB_CMP_RESET ), you see the cumulative statistics since InnoDB was started. For the table definition, see Section 26.4.6, “The INFORMATION_SCHEMA INNODB_CMP and INNODB_CMP_RESET Tables” . The  INNODB_CMPMEM  and  INNODB_CMPMEM_RESET  tables provide status information about compressed pages that reside in the buffer pool. Please consult Section 15.9, “InnoDB Table and Page Compression” for further information on compressed tables and the use of the buffer pool. The  INNODB_CMP  and INNODB_CMP_RESET  tables should provide more useful statistics on compression. InnoDB  uses a buddy allocator system to manage memory allocated to pages of various sizes, from 1KB to 16KB. Each row of the two tables described here corresponds to a single page size. The  INNODB_CMPMEM  and  INNODB_CMPMEM_RESET  tables have identical contents, but reading from INNODB_CMPMEM_RESET  resets the statistics on relocation operations. For example, if every 60 minutes you archived the output of  INNODB_CMPMEM_RESET , it would show the hourly statistics. If you never read  INNODB_CMPMEM_RESET  and monitored the output of  INNODB_CMPMEM  instead, it would show the cumulative statistics since  InnoDB  was started. For the table definition, see Section 26.4.7, “The INFORMATION_SCHEMA INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables” . The following is sample output from a database that contains compressed tables (see Section 15.9, “InnoDB Table and Page Compression” ,  INNODB_CMP ,  INNODB_CMP_PER_INDEX , and INNODB_CMPMEM ). The following table shows the contents of  INFORMATION_SCHEMA.INNODB_CMP  under a light workload. The only compressed page size that the buffer pool contains is 8K. Compressing or uncompressing pages has consumed less than a second since the time the statistics were reset, because the columns COMPRESS_TIME  and  UNCOMPRESS_TIME  are zero. According to  INNODB_CMPMEM , there are 6169 compressed 8KB pages in the buffer pool. The only other allocated block size is 64 bytes. The smallest  PAGE_SIZE  in  INNODB_CMPMEM  is used for block page size compress ops compress ops ok compress time uncompress ops uncompress time 1024 0 0 0 0 0 2048 0 0 0 0 0 4096 0 0 0 0 0 8192 1048 921 0 61 0 16384 0 0 0 0 0 15.15.1.2 INNODB_CMPMEM and INNODB_CMPMEM_RESET Internal Details 15.15.1.3 Using the Compression Information Schema Tables Example 15.1 Using the Compression Information Schema Tables 3299