title: Django transactions locking tables
body: <p>I need to upadte, add and delete rows from the auth.models.User table, unfortunately...</p>
  
  <p>when I do so the table locks and I cannot perform any SELECT queries against the table.</p>
  
  <hr>
  
  <p>I'm surrounding these queries by <code>@transaction.commit_manually</code>, which might have something to do with the tables locking.</p>
  
  <p>The transaction look like the following:</p>
  
  <pre><code>for row in csv_reader:
  
      update_sql = "UPDATE auth_user SET last_name = '%s' WHERE username = '%s'" %(row[2], row[0] )
      cursor.execute(update_sql)
      if not index % 100: print index:
          print index
          transaction.commit()
  </code></pre>
  
  <p>Also I'm using <strong>Sql Server 2008</strong>, I would like to know if it's Sql Server specific or such actions would lock the table in PostgreSQL and MySQL too.</p>
  
  <hr>
  
  <p>Any ideas guys? :)</p>