How does subpartitioning actually work and what physical files are created?
Sample in Windows

I ran the following on my Laptop in MySQL 5.6.15

mysql&gt; use test
Database changed
mysql&gt; drop table if exists nums_composite;
Query OK, 0 rows affected (0.70 sec)

mysql&gt; create table nums_composite (
    -&gt; id int, happened datetime not null,
    -&gt; primary key (id, happened)
    -&gt; ) engine=InnoDB
    -&gt; partition by range (hour(happened))
    -&gt; subpartition by hash(id) subpartitions 2
    -&gt; (partition p0 values less than (10),
    -&gt; partition p1 values less than (20),
    -&gt; partition p2 values less than MAXVALUE);
Query OK, 0 rows affected (1.91 sec)

mysql&gt; show create table nums_composite\G
*************************** 1. row ***************************
       Table: nums_composite
Create Table: CREATE TABLE `nums_composite` (
  `id` int(11) NOT NULL DEFAULT '0',
  `happened` datetime NOT NULL,
  PRIMARY KEY (`id`,`happened`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE (hour(happened))
SUBPARTITION BY HASH (id)
SUBPARTITIONS 2
(PARTITION p0 VALUES LESS THAN (10) ENGINE = InnoDB,
 PARTITION p1 VALUES LESS THAN (20) ENGINE = InnoDB,
 PARTITION p2 VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.01 sec)

mysql&gt;


I went to the OS and ran the following:

C:\&gt;cd \MySQL_5.6.15\data\test

C:\MySQL_5.6.15\data\test&gt;dir nums_comp*
 Volume in drive C is TI10665200H
 Volume Serial Number is A273-2EFF

 Directory of C:\MySQL_5.6.15\data\test

08/31/2014  04:09 PM            98,304 nums_composite#p#p0#sp#p0sp0.ibd
08/31/2014  04:09 PM            98,304 nums_composite#p#p0#sp#p0sp1.ibd
08/31/2014  04:09 PM            98,304 nums_composite#p#p1#sp#p1sp0.ibd
08/31/2014  04:09 PM            98,304 nums_composite#p#p1#sp#p1sp1.ibd
08/31/2014  04:09 PM            98,304 nums_composite#p#p2#sp#p2sp0.ibd
08/31/2014  04:09 PM            98,304 nums_composite#p#p2#sp#p2sp1.ibd
08/31/2014  04:09 PM             8,594 nums_composite.frm
08/31/2014  04:09 PM                96 nums_composite.par
               8 File(s)        598,514 bytes
               0 Dir(s)  686,691,409,920 bytes free

C:\MySQL_5.6.15\data\test&gt;


Reason you cannot see the files ?

I can see my data files because I have innodb_file_per_table enabled by default in MySQL 5.6.

mysql&gt; show global variables like 'innodb_file_per_table';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| innodb_file_per_table | ON    |
+-----------------------+-------+
1 row in set (0.00 sec)

mysql&gt;


In your case, you must have innodb_file_per_table disabled. The actual table was inside the system tablespace file ibdata1 (usually located in /var/lib/mysql)

My Guess


You are using a version before MySQL 5.6
innodb_file_per_table is set to 0 because of one of the following:

You are running on defaults (no my.cnf)
You have my.cnf with innodb_file_per_table=0



How to fix this:

STEP #1 : Enable innodb_file_per_table

Add this to the my.cnf

innodb_file_per_table=1


STEP 2 : Restart mysql

service mysql restart


STEP 3 : Regenerate the table

CREATE TABLE nums_composite_new LIKE nums_composite;
INSERT INTO nums_composite_new SELECT * FROM  nums_composite;
ALTER TABLE nums_composite RENAME nums_composite_old;
ALTER TABLE nums_composite_new RENAME nums_composite;
DROP TABLE nums_composite_old;


The .ibd files should now be visible

GIVE IT A TRY !!!

UPDATE 2014-08-31 16:37 EDT

You asked me


  I am in ubuntu.Does it change anything? 


The only thing that changes is where my.cnf should be. Run this

ls -l /etc/mysql/my.cnf


If the file exists, open it in an editor and add innodb_file_per_table=1 under the [mysql] header

If the file does not exist, run this

echo "[mysqld]" &gt; /etc/mysql/my.cnf
echo "innodb_file_per_table=1" &gt;&gt; /etc/mysql/my.cnf


Then, you can do STEP 2 and STEP 3