title: Spark SQL: ALTER TABLE CHANGE
body: <p>I want to import a few tables into a DB which (at the moment) doesn't support decimal precision greater than 18. So i tried ALTER TABLE in Spark like this to lower the precision. It isn't important how it's rounded.</p>
  
  <pre><code>rt_rel_acc_acc.saveAsTable("rt_rel_acc_acc", SaveMode.Overwrite)
  hiveContext.sql("ALTER TABLE rt_rel_acc_acc CHANGE REL001 REL001 decimal(18, 9)")
  hiveContext.read.table("rt_rel_acc_acc").write.jdbc(url, "rt_rel_acc_acc", properties)
  </code></pre>
  
  <p>However Spark doesn't seem to apply the changes at all, since an Exception is thrown at the third line:</p>
  
  <pre><code>PSQLException: ERROR: invalid numeric size '30,15'
  </code></pre>
  
  <p>ALTER TABLE x RENAME TO y is applied immediately on the other hand.</p>
  
  <p>Any idea, what's wrong with my approach?</p>