MySQL 5.5 Release Notes
[+/-]
As InnoDB evolves, data file formats that are not
compatible with prior versions of InnoDB are
sometimes required to support new features. To help manage
compatibility in upgrade and downgrade situations, and systems that
run different versions of MySQL, InnoDB uses
named file formats. InnoDB currently supports two
named file formats, Antelope
and Barracuda.
Antelope is the original
InnoDBfile format, which previously did not have a name. It supports COMPACT and REDUNDANT row formats forInnoDBtables and is the default file format in MySQL 5.5 to ensure maximum compatibility with earlier MySQL versions that do not support the Barracuda file format.Barracuda is the newest file format. It supports all
InnoDBrow formats including the newer COMPRESSED and DYNAMIC row formats. The features associated with COMPRESSED and DYNAMIC row formats include compressed tables and efficient storage of off-page columns. See Section 14.14, “InnoDB Row Storage and Row Formats”.
This section discusses enabling InnoDB file
formats, verifying compatibility of different file formats between
MySQL releases, identifying the file format in use, and downgrading
the file format.