presto-blackhole/src/main/java/io/prestosql/plugin/blackhole/BlackHoleNodePartitioningProvider.java/BlackHoleNodePartitioningProvider/getBucketNodeMap
class BlackHoleNodePartitioningProvider:    @Override
    public ConnectorBucketNodeMap getBucketNodeMap(ConnectorTransactionHandle transactionHandle, ConnectorSession session, ConnectorPartitioningHandle partitioningHandle)
    {
        // create one bucket per node
        return createBucketNodeMap(nodeManager.getRequiredWorkerNodes().size());
    }