normalization.add(new RemoveUnusedTreatRule());
normalization.add(new RemoveRedundantVariablesRule());
normalization.add(new RemoveUnusedAssignAndAggregateRule());
// Find unnest followed by aggregate in a subplan.
normalization.add(new EliminateUnnestAggregateSubplanRule());
normalization.add(new RemoveRedundantVariablesRule());
normalization.add(new RemoveUnusedAssignAndAggregateRule());
// Remove single tuple input subplans and merge unnest aggregate operators.
// TODO Fix EliminateSubplanForSinglePathsRule to check for variables used after the subplan.