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15.14.1.2 INNODB_CMPMEM and INNODB_CMPMEM_RESET
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.
Internal Details
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 25.39.6, “The INFORMATION_SCHEMA INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables”.
Document created the 26/06/2006, last modified the 26/10/2018
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