title: need to order query results when inserting into table with sort key?
body: <p>I'm responsible for process that truncates a Redshift table then repopulates it via a select query from another table.</p>
  
  <p>The target table (that is truncated and reloaded) has a sort key.</p>
  
  <p>My understanding was that I needed to use an "order by" on the select so that the data goes into the (empty) target table in sorted order, but I'm seeing some behavior that suggests that might not be the case.</p>
  
  <p>To test, I took an existing table that was ~70% unsorted (as reported by svv_table_info).  I created a new table with the exact same structure, including diststyle and sort key, then populated it by a "select *" from the unsorted table <em>with no "order by" clause</em>.</p>
  
  <p>The <em>new</em> table showed up as 0% unsorted in svv_table_info, i.e. it's apparently sorted.</p>
  
  <p>How/why is that possible?</p>