InnoDB File Format
Contents
Prior to MariaDB 10.3, the InnoDB storage engine supports two different file formats.
Setting a Table's File Format
In MariaDB 10.2 and before, the default file format for InnoDB tables can be chosen by setting the innodb_file_format.
In MariaDB 10.2.1 and before, the default file format isAntelope. In MariaDB 10.2.2 and later, the default file format is Barracuda and Antelope is deprecated.
A table's tablespace is tagged with the lowest InnoDB file format that supports the table's row format. So, even if the Barracuda file format is enabled, tables that use the COMPACT or REDUNDANT row formats will be tagged with the Antelope file format in the information_schema.INNODB_SYS_TABLES table.
Supported File Formats
The InnoDB storage engine supports two different file formats:
AntelopeBarracuda
Antelope
In MariaDB 10.2.1 and before, the default file format is Antelope. In MariaDB 10.2.2 and later, the Antelope file format is deprecated.
Antelope is the original InnoDB file format. It supports the COMPACT and REDUNDANT row formats, but not the DYNAMIC or COMPRESSED row formats.
Barracuda
In MariaDB 10.1 and before, the Barracuda file format is only supported if the innodb_file_per_table system variable is set to ON. In MariaDB 10.2.2 and later, the default file format is Barracuda and Antelope is deprecated.
Barracuda is a newer InnoDB file format. It supports the COMPACT, REDUNDANT, DYNAMIC and COMPRESSED row formats. Tables with large BLOB or TEXT columns in particular could benefit from the dynamic row format.
Future Formats
InnoDB might use new file formats in the future. Each format will have an identifier from 0 to 25, and a name. The names have already been decided, and are animal names listed in an alphabetical order: Antelope, Barracuda, Cheetah, Dragon, Elk, Fox, Gazelle, Hornet, Impala, Jaguar, Kangaroo, Leopard, Moose, Nautilus, Ocelot, Porpoise, Quail, Rabbit, Shark, Tiger, Urchin, Viper, Whale, Xenops, Yak and Zebra.
Checking a Table's File Format.
The information_schema.INNODB_SYS_TABLES table can be queried to see the file format used by a table.
A table's tablespace is tagged with the lowest InnoDB file format that supports the table's row format. So, even if the Barracuda file format is enabled, tables that use the COMPACT or REDUNDANT row formats will be tagged with the Antelope file format in the information_schema.INNODB_SYS_TABLES table.
Compatibility
Each tablespace is tagged with the id of the most recent file format used by one of its tables. All versions of InnoDB can read tables that use an older file format. However, it can not read from more recent formats. For this reason, each time InnoDB opens a table it checks the tablespace's format, and returns an error if a newer format is used.
This check can be skipped via the innodb_file_format_check variable. Beware that, is InnoDB tries to repair a table in an unknown format, the table will be corrupted! This happens on restart if innodb_file_format_check is disabled and the server crashed, or it was closed with fast shutdown.
To downgrade a table from the Barracuda format to Antelope, the table's ROW_FORMAT can be set to a value supported by Antelope, via an ALTER TABLE statement. This recreates the indexes.
The Antelope format can be used to make sure that tables work on MariaDB and MySQL servers which are older than 5.5.
