Because InnoDB 1.1 supports the “Barracuda” file format, with new on-disk data structures within both the database and log files, pay special attention to file format compatibility with respect to the following scenarios:
Downgrading from MySQL 5.5 to the MySQL 5.1 or earlier (without the InnoDB Plugin enabled), or otherwise using earlier versions of MySQL with database files created by MySQL 5.5 and higher.
Using
mysqldump.Using MySQL replication.
Using MySQL Enterprise Backup or InnoDB Hot Backup.
WARNING: Once you create any
tables with the Barracuda file format, take care to avoid crashes
and corruptions when using those files with an earlier version of
InnoDB. It is strongly
recommended that you use a “slow shutdown”
(SET GLOBAL innodb_fast_shutdown=0) when
stopping the MySQL server before downgrading to MySQL 5.1 or
earlier. This ensures that the log files and other system
information do not cause problems when using a prior version of
InnoDB. See Section 13.7.11.3, “How to Downgrade”.
WARNING: If you dump a database
containing compressed tables with mysqldump,
the dump file may contain CREATE
TABLE statements that attempt to create compressed
tables, or those using ROW_FORMAT=DYNAMIC in the new database.
Therefore, be sure the new database is running the
InnoDB storage engine, with the proper settings for innodb_file_format
and innodb_file_per_table, if you want to have the tables
re-created as they exist in the original database. Typically, when
the mysqldump file is loaded, MySQL and
InnoDB ignore CREATE TABLE
options they do not recognize, and the table(s) are created in a
format used by the running server.
WARNING: If you use MySQL
replication, ensure all slaves are configured with the
InnoDB storage engine, with the same settings for innodb_file_format
and innodb_file_per_table. If you do not do so, and you create
tables that require the new “Barracuda” file format, replication
errors may occur. If a slave MySQL server is running an older
version of MySQL, it ignores the CREATE
TABLE options to create a compressed table or one with
ROW_FORMAT=DYNAMIC, and creates the table uncompressed, with
ROW_FORMAT=COMPACT.
WARNING: Version 3.0 of
InnoDB Hot Backup does not support the new “Barracuda” file format.
Using InnoDB Hot Backup Version 3 to backup databases in this format
causes unpredictable behavior. MySQL Enterprise Backup, the successor product to
InnoDB Hot Backup, does support tables with the Barracuda file format.
You can also back up such databases with
mysqldump.