presto-main/src/main/java/io/prestosql/sql/planner/PlanFragmenter.java/GroupedExecutionTagger/processWindowFunction
class GroupedExecutionTagger:        private GroupedExecutionProperties processWindowFunction(PlanNode node)
        {
            GroupedExecutionProperties properties = getOnlyElement(node.getSources()).accept(this, null);
            if (groupedExecutionEnabled && properties.isCurrentNodeCapable()) {
                return new GroupedExecutionProperties(true, true, properties.capableTableScanNodes);
            }
            return GroupedExecutionProperties.notCapable();
        }