#### 15.15.1.2 INNODB\_CMPMEM and INNODB\_CMPMEM\_RESET

[]()[]()[]()

 The [`INNODB_CMPMEM`](information-schema-innodb-cmpmem-table.html) and [`INNODB_CMPMEM_RESET`](information-schema-innodb-cmpmem-table.html) tables provide status information about compressed pages that reside in the buffer pool. Please consult [Section 15.9, “InnoDB Table and Page Compression”](innodb-compression.html) for further information on compressed tables and the use of the buffer pool. The [`INNODB_CMP`](information-schema-innodb-cmp-table.html) and [`INNODB_CMP_RESET`](information-schema-innodb-cmp-table.html) tables should provide more useful statistics on compression.

##### Internal Details

`InnoDB` uses a [buddy allocator](glossary.html#glos_buddy_allocator) system to manage memory allocated to [pages of various sizes](glossary.html#glos_page_size), from 1KB to 16KB. Each row of the two tables described here corresponds to a single page size.

 The [`INNODB_CMPMEM`](information-schema-innodb-cmpmem-table.html) and [`INNODB_CMPMEM_RESET`](information-schema-innodb-cmpmem-table.html) tables have identical contents, but reading from [`INNODB_CMPMEM_RESET`](information-schema-innodb-cmpmem-table.html) resets the statistics on relocation operations. For example, if every 60 minutes you archived the output of [`INNODB_CMPMEM_RESET`](information-schema-innodb-cmpmem-table.html), it would show the hourly statistics. If you never read [`INNODB_CMPMEM_RESET`](information-schema-innodb-cmpmem-table.html) and monitored the output of [`INNODB_CMPMEM`](information-schema-innodb-cmpmem-table.html) 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”](information-schema-innodb-cmpmem-table.html).

