title: MySQL: Alter Statement causes Table Lock after finish
body: <p>I add a column to a INNODB table with 5.6GB data (200k rows), 50 columns and 6 indexes.
  The statement took 2 minutes to execute and the new column shows up in the <em>SHOW CREATE TABLE</em> command.</p>
  
  <p>After some minutes (or perhaps immediately) all INSERTS statements keeps in state <em>sending data</em> according to the processlist and the opened table counter increases rapidly. The server load went crazy too.</p>
  
  <p>I couldn't figure out which process locks the table nor do I have any explanation for this. In the end I just restarted the MySQL Server (5.5) and everything works fine.</p>
  
  <p>Could a FLUSH (<a href="http://dev.mysql.com/doc/refman/5.5/en/flush.html" rel="nofollow">http://dev.mysql.com/doc/refman/5.5/en/flush.html</a>) helps in this situation? Are there some settings wrong? I mostly have the default values.</p>