title: JPA findBy...IgnoreCase and PostgreSQL indexing
body: <p>I have following question about <code>findByUsernameIgnoreCase</code> lookup and indexing.
  For example i have DB column <code>username</code> (unique index) in <code>users</code> table and i want case insensitive lookup.
  For now all the records are in UPPERCASE.</p>
  
  <p>The question is <code>findByUsernameIgnoreCase(...)</code> will use the indexing or not?</p>
  
  <p>In specification the outcome of IgnoreCase is <code>where UPPER(username)=UPPER(?1)</code> which confuses me in order of index.</p>