// hash build
OperatorFactory ordersTableScan = createTableScanOperator(0, "orders", "orderkey", "totalprice");
HashBuilderOperatorFactory hashBuilder = new HashBuilderOperatorFactory(1, ordersTableScan.getTypes(), Ints.asList(0), 1_500_000);
DriverFactory hashBuildDriverFactory = new DriverFactory(true, false, ordersTableScan, hashBuilder);
Driver hashBuildDriver = hashBuildDriverFactory.createDriver(taskContext.addPipelineContext(true, false).addDriverContext());
// join
OperatorFactory lineItemTableScan = createTableScanOperator(0, "lineitem", "orderkey", "quantity");
OperatorFactory joinOperator = LookupJoinOperators.innerJoin(1, hashBuilder.getLookupSourceSupplier(), lineItemTableScan.getTypes(), Ints.asList(0));
NullOutputOperatorFactory output = new NullOutputOperatorFactory(2, joinOperator.getTypes());
DriverFactory joinDriverFactory = new DriverFactory(true, true, lineItemTableScan, joinOperator, output);
Driver joinDriver = joinDriverFactory.createDriver(taskContext.addPipelineContext(true, true).addDriverContext());
return ImmutableList.of(hashBuildDriver, joinDriver);
}