MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
There are two pairs of InnoDB
INFORMATION_SCHEMA tables about compression
that can provide insight into how well compression is working
overall:
INNODB_CMP and
INNODB_CMP_RESET provide
information about the number of compression operations and the
amount of time spent performing compression.
INNODB_CMPMEM and
INNODB_CMPMEM_RESET provide
information about the way memory is allocated for compression.