title: MySQL + MyISAM table size question
body: <p>I have a test table.  The test table is as follows:</p>
  
  <pre><code>CREATE TABLE  `mytest` (
    `num1` int(10) unsigned NOT NULL,
    KEY `key1` (`num1`)
  ) ENGINE=MyISAM DEFAULT CHARSET=latin1;
  </code></pre>
  
  <p>I inserted 50 million rows in this table.</p>
  
  <p>When I do show table status the avg_row_length is 7.  I was expecting to see 4 since mySQL uses 4 bytes for integers.  Does the key have an effect on the avg_row_length?  When I look at my .MYD file the size is 334 MB which is exactly what it should be given that the avg_row_length is 7, however I was really expecting to see 190 MB given that I only have an int.</p>
  
  <pre><code>+----------------+--------+---------+------------+----------+----------------+-------------+------------------+--------------+-----------+----------------+---------------------+---------------------+------------+-------------------+----------+----------------+---------+
  | Name           | Engine | Version | Row_format | Rows     | Avg_row_length | Data_length | Max_data_length  | Index_length | Data_free | Auto_increment | Create_time         | Update_time         | Check_time | Collation         | Checksum | Create_options | Comment |
  +----------------+--------+---------+------------+----------+----------------+-------------+------------------+--------------+-----------+----------------+---------------------+---------------------+------------+-------------------+----------+----------------+---------+
  | mytest         | MyISAM |      10 | Fixed      | 50000000 |              7 |   350000000 | 1970324836974591 |    600518656 |         0 |           NULL | 2010-05-22 09:15:06 | 2010-05-22 19:32:53 | NULL       | latin1_swedish_ci |     NULL |                |         |
  </code></pre>
  
  <p>I have included the output of show table status for mytest table.  Sorry about the formatting :D
  Thanks in advance!</p>
  
  <p>Alessandro Ferrucci</p>