presto-main/src/main/java/io/prestosql/sql/planner/DistributedExecutionPlanner.java/DistributedExecutionPlanner/visitValues
class DistributedExecutionPlanner:        @Override
        public Map<PlanNodeId, SplitSource> visitValues(ValuesNode node, Void context)
        {
            // values node does not have splits
            return ImmutableMap.of();
        }