Solr Sorting - uppercase value first or lowercase value

Question

We are indexing our objects into Solr and let users to sort by different name. The sort field is defined as specified below in schema.xml:

<fieldType name="sortabletext" class="solr.TextField" sortMissingLast="true" positionIncrementGap="100">
    <analyzer>
        <tokenizer class="solr.KeywordTokenizerFactory"/>
        <filter class="solr.LowerCaseFilterFactory" />
        <filter class="solr.TrimFilterFactory" />
    </analyzer>
</fieldType>

In case I have the following name in my data

1. Test
2. West
3. itest
4. end

while using the Solr sorting by name, the upper case comes first followed by lower cases like

1. Test
2. West
3. end
4. itest

I think this is happening since since the ASCII uppercase codes are smaller than lower case but from user side this is not a good experience.Is there way I can customize this behavior similar to if I run the similar query on the database?

Answer 1

Standard TextFields don't sort intuitively because they are analyzed into tokens and the pre-analyzed (raw) field value isn't stored because it is generally very long.

Luckily, solr offers a SortableTextField which will store the first 1024 (though this is configurable) characters of the pre-analyzed field value as a doc values field which it will use when sorting the SortableTextField