title: Linq query using Equal is very slow, but contains not
body: <p>I have a problem using linq:
  query that use "=" is very slow, I create it in this way:</p>
  
  <pre><code>predicate = predicate.And(p =&gt; p.Fields.Any(f =&gt; f.Name == name &amp;&amp; f.ExpectedValue == value));
  </code></pre>
  
  <p>But, the "same" query using "Contains" is fast:</p>
  
  <pre><code>predicate = predicate.And(p =&gt; p.Fields.Any(f =&gt; f.Name == name &amp;&amp; f.ExpectedValue.Contains(value)));
  </code></pre>
  
  <p>On my table I have indexes on "Name" and on "ExpectedValue".</p>
  
  <p>Any suggestion?</p>