presto-main/src/main/java/io/prestosql/sql/planner/LocalExecutionPlanner.java/Visitor/visitTableScan
class Visitor:        @Override
        public PhysicalOperation visitTableScan(TableScanNode node, LocalExecutionPlanContext context)
        {
            List<ColumnHandle> columns = new ArrayList<>();
            for (Symbol symbol : node.getOutputSymbols()) {
                columns.add(node.getAssignments().get(symbol));
            }

            OperatorFactory operatorFactory = new TableScanOperatorFactory(context.getNextOperatorId(), node.getId(), pageSourceProvider, node.getTable(), columns);
            return new PhysicalOperation(operatorFactory, makeLayout(node), context, stageExecutionDescriptor.isScanGroupedExecution(node.getId()) ? GROUPED_EXECUTION : UNGROUPED_EXECUTION);
        }