title: KeywordTokenizerFactory with LowerCaseFilterFactory
body: <p>I wanted to use a NGramFilterFactory for my index and saw following example and tryed it out:</p>
  
  <pre><code>&lt;fieldType name="NGramText" class="solr.TextField" positionIncrementGap="100"&gt;
   &lt;analyzer type="index"&gt;
     &lt;tokenizer class="solr.KeywordTokenizerFactory"/&gt;  
     &lt;filter class="solr.LowerCaseFilterFactory"/&gt; 
     &lt;filter class="solr.NGramFilterFactory" minGramSize="2" maxGramSize="25" /&gt;
  
   &lt;/analyzer&gt;
   &lt;analyzer type="query"&gt;
   &lt;tokenizer class="solr.KeywordTokenizerFactory"/&gt;
   &lt;filter class="solr.LowerCaseFilterFactory"/&gt;
   &lt;/analyzer&gt;
  &lt;/fieldType&gt;
  
  
  &lt;field name="mark" type="NGramText" indexed="true" stored="true" omitNorms="true" omitTermFreqAndPositions="true"/&gt;
  </code></pre>
  
  <p>The example is using KeywordTokenizerFactory. What is the purpose of using this? From what i understand it really do not do anythig, " the entire
  input string is preserved as a single token " it says on the net. </p>
  
  <p>Is there a good reason to use KeywordTokenizerFactory to make Ngrams or could i change it for WhitespaceTokenizerFactory with out slowing down the searches?</p>
  
  <p>And also with this example LowerCaseFilterFactory is not making the fields lowercase could that has something to do with the conjunction with KeywordTokenizerFactory?</p>