title: DataTable Load very slow
body: <p>I'm using a datatable as the datasource of some dropdowns on a page, but have noticed that the page is very slow during the postbacks.</p>
  
  <p>I've tracked it through to here:</p>
  
  <pre><code>DataTable dt = new DataTable();
  dt.Load(sqlCmd.ExecuteReader()); // this takes ages
  </code></pre>
  
  <p>The sql command is a parametrised query, not a stored procedure (the return values and where are quite 'dynamic' so this wouldn't be practicable), but nevertheless a simple select union query. 
  Usually returns between 5 and 20 options per dropdown, depending on what's been selected on the other dropdowns.
  When I run the query in the management studio, it's done in under a second. Here it can take up to 7 seconds per dropdown, with 6 dropdowns on the page it soon adds up.
  I have also tried with a SqlDataAdapter:</p>
  
  <pre><code>SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd);
  sqlDa.Fill(dt); // this takes ages
  </code></pre>
  
  <p>but this was just as slow.
  I have this on 2 different systems and on both have the same performance issues.</p>
  
  <p>If anyone knows a better (faster) methord, or knows why this is so slow that would be great.</p>