Django-Haystack autoquery gives strange results with solr backend

Question

I am using django 1.5 along with haystack 2.1.0.

While using auto-query on one of the models I found the following behavior.

test_search = "charles ken"

SearchQuerySet().models(Foo, FooSome, FooGone).auto_query(test_search) 

The above query gives multiple results.

test_search = "charles k"

SearchQuerySet().models(Foo, FooSome, FooGone).auto_query(test_search)

The above query gives no results. What am I doing wrong ?

Edit :

The field in concern is edge_ngram

<fieldType name="edge_ngram" class="solr.TextField" positionIncrementGap="1">
      <analyzer type="index">
        <tokenizer class="solr.WhitespaceTokenizerFactory" />
        <filter class="solr.LowerCaseFilterFactory" />
        <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="0" catenateNumbers="0" catenateAll="0" splitOnCaseChange="1"/>
        <filter class="solr.EdgeNGramFilterFactory" minGramSize="2" maxGramSize="15" side="front" />
      </analyzer>
      <analyzer type="query">
        <tokenizer class="solr.WhitespaceTokenizerFactory" />
        <filter class="solr.LowerCaseFilterFactory" />
        <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="0" catenateNumbers="0" catenateAll="0" splitOnCaseChange="1"/>
      </analyzer>
    </fieldType>

Answer 1

You need to change the minGramSize here to 1

<fieldType name="edge_ngram" class="solr.TextField" positionIncrementGap="1">
      <analyzer type="index">
        <tokenizer class="solr.WhitespaceTokenizerFactory" />
        <filter class="solr.LowerCaseFilterFactory" />
        <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="0" catenateNumbers="0" catenateAll="0" splitOnCaseChange="1"/>
        <filter class="solr.EdgeNGramFilterFactory" minGramSize="1" maxGramSize="15" side="front" />
      </analyzer>
      <analyzer type="query">
        <tokenizer class="solr.WhitespaceTokenizerFactory" />
        <filter class="solr.LowerCaseFilterFactory" />
        <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="0" catenateNumbers="0" catenateAll="0" splitOnCaseChange="1"/>
      </analyzer>
    </fieldType>

But I would recommend to have minGramSize=2 or 3 as it would avoid to many indexes.