title: MySQL SET timestamp as a Slow Query
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/2832912/how-can-set-timestamp-be-a-slow-query">How can &ldquo;set timestamp&rdquo; be a slow query?</a>  </p>
  </blockquote>
  
  
  
  <p>I am running a web application and Wordpress blog using PHP and MySQL 5.1, residing on a VPS server. The slow query log is showing many entries for items that should not be taking very long to complete. The strange thing is that it when I click on my blog link, it usually take a long time to load initially, but after that it is pretty quick. Then in a few hours it is back to the slow first click again. It seems as if the "SET timestamp= " query is present in nearly all of the slow entries. Here is an example of what it looks like:</p>
  
  <pre>
  # Time: 110129  4:02:06
  # User@Host: appsadmin[appsadmin] @ localhost []
  # Query_time: 1.367264  Lock_time: 0.000043 Rows_sent: 18  Rows_examined: 18
  use apps;
  SET timestamp=1296291726;
  show tables;
  # Time: 110129  4:02:07
  # User@Host: wp_user[wp_user] @ localhost []
  # Query_time: 0.635450  Lock_time: 0.000041 Rows_sent: 11  Rows_examined: 11
  use wordpress_user;
  SET timestamp=1296291727;
  show tables;
  # Time: 110130  4:02:03
  # User@Host: appsadmin[appsadmin] @ localhost []
  # Query_time: 0.592159  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0
  use apps;
  SET timestamp=1296378123;
  SELECT /*!40001 SQL_NO_CACHE */ * FROM `mail_queue`;
  # Time: 110131  4:02:08
  # User@Host: appsadmin[appsadmin] @ localhost []
  # Query_time: 2.789990  Lock_time: 0.000047 Rows_sent: 18  Rows_examined: 18
  SET timestamp=1296464528;
  show tables;
  # Time: 110131  4:02:09
  # User@Host: wp_user[wp_user] @ localhost []
  # Query_time: 0.535981  Lock_time: 0.000041 Rows_sent: 11  Rows_examined: 11
  use wordpress_user;
  SET timestamp=1296464529;
  show tables;
  # Time: 110201  3:19:03
  # User@Host: wp_user[wp_user] @ localhost []
  # Query_time: 1.401393  Lock_time: 0.000071 Rows_sent: 120  Rows_examined: 145
  SET timestamp=1296548343;
  SELECT option_name, option_value FROM wp_options WHERE autoload = 'yes';
  </pre>
  
  <p>This shows that it is not an issue with my DB design, but some kind of configuration problem.</p>