Apache Dovecot Solr does not work with partial email addresses

Question

Why does a search in Roundcube not return a result when using a partial address like 'tes' instead of 'test' when using Apache Dovecot Solr 

Answer

When using Dovecot Solr and searching partial email addresses, each "word" of the email is looked at. Dovecot Solr applies the search to all keywords. In the case of "test.user", either "test" or "user" will return, but not "use" or "tes".