title: when to prefer pessimistic model of transaction isolation over optimistic one?
body: <p>Do I understand correctly that table/row lock hints are being used for pessimistic transaction (TX) isolation models of concurrency <strong>ONLY</strong>?<br>
  In other words, when can table/row lock hints be used during engagement of optimistic TX isolation provided by SQL Server (2005 and higher)?     </p>
  
  <p>When one would need pessimistic TX isolation levels/hints in SQL Server2005+ if the later provides built-in optimistic (aka snapshot aka versioning) concurrency isolation?<br>
  I did read that pessimistic options are legacy and are not needed anymore, though I am in doubt.  </p>
  
  <p>Also, having optimistic (aka snapshot aka versioning) TX isolation levels  built-in SQL Server2005+, 
  when one would need to manually code for optimistic concurrency  features?  </p>
  
  <p>The last question is inspired by having read:  </p>
  
  <ul>
  <li><a href="http://decipherinfosys.wordpress.com/2007/09/28/optimistic-concurrency-in-sql-server/" rel="nofollow">"Optimistic Concurrency in SQL Server" (September 28, 2007)</a></li>
  </ul>
  
  <p>describing custom coding to provide versioning in SQL Server.  </p>