title: Cannot do normal select in mysql database
body: <p>I try to do normal select on database, like <code>select * from xxx limit 0,30</code>.</p>
  
  <p>But I get this message : <code>ERROR 29 (HY000): File 'tablename.MYD' not found (Errcode: 13)</code></p>
  
  <p>I try to search the file on mysql datafile folder, and I find it. How can this happen.</p>