title: Is there a procedure required for updating mysql column types?
body: <p>I'm trying to optimize my mysql tables (MyISAM) and I changed some column types with phpmyadmin, mostly from int to smallint, medium int, etc. After I did that mysql really bogged down and the server load went really high. I did this on a live site, which I figured was the problem, but even after putting the site into maintenance mode and waiting for the load to drop down, the load still went crazy afterwards. In the end I have to drop the tables and recreate them with their original column types for things to work back smoothly... So is there anything special I should be doing before and after changing column types?</p>
  
  <p>Would joining tables with two different column types also create a problem? I.E. id INT(11) joining with MEDIUMINT(8). I think at one point I did that.</p>