presto-main/src/main/java/io/prestosql/sql/planner/FragmentTableScanCounter.java/FragmentTableScanCounter/visitExchange
class FragmentTableScanCounter:        @Override
        public Integer visitExchange(ExchangeNode node, Void context)
        {
            if (node.getScope() == ExchangeNode.Scope.REMOTE) {
                return 0;
            }
            return visitPlan(node, context);
        }