presto-mongodb/src/main/java/io/prestosql/plugin/mongodb/MongoConnector.java/MongoConnector/rollback
class MongoConnector:    @Override
    public void rollback(ConnectorTransactionHandle transaction)
    {
        MongoMetadata metadata = transactions.remove(transaction);
        checkArgument(metadata != null, "no such transaction: %s", transaction);
        metadata.rollback();
    }