title: Query very slow after a few execution
body: <p>I'm new of oracle and now I'm becoming crazy with the following situation. I'm working on a oracle 11g database and many times is happening that I run a query with sql developer and this is correctly executed in 5/6 seconds, others time instead the same query take 300/400 second to be executed. There is some tools to debug what is happening when the query employs 300/400 second?</p>
  
  <p><strong>Update 1</strong>
   This is my sql developer screenshot the problem seems be <em>direct path read temp</em></p>
  
  <p><img src="https://i.stack.imgur.com/PKNPh.png" alt="enter image description here"></p>
  
  <p><strong>Update 2</strong>
  <a href="https://www.dropbox.com/s/kcy8j2qacpzcgzp/export.csv?dl=0" rel="nofollow noreferrer">report</a></p>
  
  <p><strong>Update 3</strong>
  <a href="https://www.dropbox.com/s/3d0em9lcrsdoih1/export2.csv?dl=0" rel="nofollow noreferrer">report2</a></p>
  
  <p>Any suggestion?</p>