title: Question on how to read a SQL Execution plan
body: <p>I have executed a query and included the Actual Execution Plan.  There is one Hash Match that is of interest to me because it's subtree uses a Index Scan instead of an index seek.  When I mouse over this Hash Match there is a section called "Probe Residual".  I had assumed that this is whatever values I am joining on.  Am I correct here or is there a better explanation of what that means?</p>
  
  <p>The second question I had is regarding the indexes it uses.  In  my example I am pretty sure this particular join is joining on two columns.  The index that it is Scanning has both of these columns in it as well as another column that is not used in the join.  I was under the impression that this would result in an Index Seek rather than a Scan.  Am I mistaken on this?</p>