Question

We’re currently using MySQL with innodb and we have some large tables that are compact in row format. When I change the row format to compressed we are still seeing the same size for the table. Anyone know the reason for this?

Answer 1

Is it possible you declared ROW_FORMAT=COMPRESSED for the table, but you did not enable the configuration value innodb_file_format=BARRACUDA?

If you don’t do the latter step, then any request for Barracuda row formats will not take effects. And such a request generates a warning:

mysql> alter table foo row_format=compressed;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 2

mysql> show warnings;
+---------+------+-----------------------------------------------------------------------+
| Level   | Code | Message                                                               |
+---------+------+-----------------------------------------------------------------------+
| Warning | 1478 | InnoDB: ROW_FORMAT=COMPRESSED requires innodb_file_format > Antelope. |
| Warning | 1478 | InnoDB: assuming ROW_FORMAT=COMPACT.                                  |
+---------+------+-----------------------------------------------------------------------+

Also, you can’t use compressed row format unless you also enable innodb_file_per_table.

mysql> alter table foo row_format=compressed;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 2

mysql> show warnings;
+---------+------+---------------------------------------------------------------+
| Level   | Code | Message                                                       |
+---------+------+---------------------------------------------------------------+
| Warning | 1478 | InnoDB: ROW_FORMAT=COMPRESSED requires innodb_file_per_table. |
| Warning | 1478 | InnoDB: assuming ROW_FORMAT=COMPACT.                          |
+---------+------+---------------------------------------------------------------+