private void compactGroups(){
  for (int i=0; i < groups.size(); i++) {
    List<Segment> group=groups.get(i);
    List<OffsetPredicate> groupPredicates=predicates.get(i);
    Segment segment=compactGroup(group,groupPredicates);
    mergeReleased(group,groupPredicates,segment);
    deleteGroup(group);
  }
}

private void compactGroups ( ) { for ( int i = 0 ; i < groups . size ( ) ; i ++ ) { List < Segment > group = groups . get ( i ) ; List < OffsetPredicate > groupPredicates = predicates . get ( i ) ; Segment segment = compactGroup ( group , groupPredicates ) ; mergeReleased ( group , groupPredicates , segment ) ; deleteGroup ( group ) ; } }
compacts all compactable segments .
