rimary record will never be changed
    after that primary record is inserted.  For immutable secondary keys, a
    best effort is made to avoid calling
    <code>SecondaryKeyCreator.createSecondaryKey</code> when a primary record
    is updated.  This optimization may reduce the overhead of an update
    operation significantly if the <code>createSecondaryKey</code> operation is
    expensive.
    <p>
    Be sure to set this property to true only if the secondary key in the
    primary record is never chan