Each InnoDB tablespace file (with a name matching
*.ibd) is tagged with the file format used to
create its table and indexes. The way to downgrade the tablespace
is to re-create the table and its indexes. The easiest way to
recreate a table and its indexes is to use the command:
on each table that you want to downgrade. The
COMPACT row format uses the file format
Antelope. It was introduced in MySQL 5.0.3.