14.2.9.5 Physical Row Structure

The physical row structure for an InnoDB table depends on the MySQL version and the optional ROW_FORMAT option used when the table was created. For InnoDB tables in MySQL 5.0.3 and earlier, only the REDUNDANT row format was available. For MySQL 5.0.3 and later, the default is to use the COMPACT row format, but you can use the REDUNDANT format to retain compatibility with older versions of InnoDB tables. To check the row format of an InnoDB table use SHOW TABLE STATUS.

The compact row format decreases row storage space by about 20% at the cost of increasing CPU use for some operations. If your workload is a typical one that is limited by cache hit rates and disk speed, compact format is likely to be faster. If the workload is a rare case that is limited by CPU speed, compact format might be slower.

Rows in InnoDB tables that use REDUNDANT row format have the following characteristics:

Rows in InnoDB tables that use COMPACT row format have the following characteristics: