The only way for you to have it is to add it to your my.cnf.
Before you can add this option, you must make sure the InnoDB storage engine is available.
Please run these commands
SHOW VARIABLES LIKE 'have_innodb';
SHOW ENGINES;
If you see this:
mysql> SHOW VARIABLES LIKE 'have_innodb';
+---------------+----------+
| Variable_name | Value |
+---------------+----------+
| have_innodb | DISABLED |
+---------------+----------+
1 row in set (0.01 sec)
mysql> SHOW ENGINES;
+------------+----------+----------------------------------------------------------------+
| Engine | Support | Comment |
+------------+----------+----------------------------------------------------------------+
| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables |
| InnoDB | NO | Supports transactions, row-level locking, and foreign keys |
| BerkeleyDB | NO | Supports transactions and page-level locking |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) |
| EXAMPLE | NO | Example storage engine |
| ARCHIVE | YES | Archive storage engine |
| CSV | YES | CSV storage engine |
| ndbcluster | DISABLED | Clustered, fault-tolerant, memory-based tables |
| FEDERATED | YES | Federated MySQL storage engine |
| MRG_MYISAM | YES | Collection of identical MyISAM tables |
| ISAM | NO | Obsolete storage engine |
+------------+----------+----------------------------------------------------------------+
12 rows in set (0.00 sec)
mysql>
then you have skip-innodb in your my.cnf. You should comment it out and restart mysql
What you want to see is this:
mysql> SHOW VARIABLES LIKE 'have_innodb';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| have_innodb | YES |
+---------------+-------+
1 row in set (0.00 sec)
mysql> SHOW ENGINES;
+------------+----------+----------------------------------------------------------------+
| Engine | Support | Comment |
+------------+----------+----------------------------------------------------------------+
| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables |
| InnoDB | YES | Supports transactions, row-level locking, and foreign keys |
| BerkeleyDB | NO | Supports transactions and page-level locking |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) |
| EXAMPLE | NO | Example storage engine |
| ARCHIVE | YES | Archive storage engine |
| CSV | YES | CSV storage engine |
| ndbcluster | DISABLED | Clustered, fault-tolerant, memory-based tables |
| FEDERATED | YES | Federated MySQL storage engine |
| MRG_MYISAM | YES | Collection of identical MyISAM tables |
| ISAM | NO | Obsolete storage engine |
+------------+----------+----------------------------------------------------------------+
12 rows in set (0.00 sec)
mysql>
Add that option to the my.cnf
[mysqld]
innodb_flush_method=O_DIRECT
then run
service mysql restart
Afterwards, you should be able to see it if you run
mysql> show variables like 'innodb_flush_method';
+---------------------+----------+
| Variable_name | Value |
+---------------------+----------+
| innodb_flush_method | O_DIRECT |
+---------------------+----------+
1 row in set (0.00 sec)
mysql>
