log file sync http://www.eygle.com/archives/2004/10/statspack14-logfilesync.html class slave wait http://space.itpub.net/122290/viewspace-589053 CPU time http://www.itpub.net/thread-641208-1-1.html log file parallel write http://blog.csdn.net/tianlesoftware/archive/2009/12/01/4916671.aspx db file scattered read http://www.eygle.com/statspack/statspack12.htm