     using gdf_col_pointer = typename std::unique_ptr<gdf_column, std::function<void(gdf_column*)>>;
     auto gdf_col_deleter = [](gdf_column* col){
         col->size = 0;
-        if (col->data) { cudaFree(col->data); }
+        if (col->data)  { cudaFree(col->data);  }
         if (col->valid) { cudaFree(col->valid); }
     };
     gdf_col_pointer l_index_temp, r_index_temp;

        for (auto &join_index : l_join_indices) {
            gdf_column_view(result_cols[i], nullptr, nullptr, join_size, left_cols[join_index]->dtype);
            int col_width; get_column_byte_width(result_cols[i], &col_width);
            cudaMalloc(&(result_cols[i]->data), col_width * join_size);
            cudaMalloc(&(result_cols[i]->valid), sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size));
            cudaMemset(result_cols[i]->valid, 0, sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size));
            ++i;
        }
    }

    for (int i = 0; i < left_table_end; ++i) {
        gdf_column_view(result_cols[i], nullptr, nullptr, join_size, lnonjoincol[i]->dtype);
        int col_width; get_column_byte_width(result_cols[i], &col_width);
        CUDA_TRY( cudaMalloc(&(result_cols[i]->data), col_width * join_size) );
        CUDA_TRY( cudaMalloc(&(result_cols[i]->valid), sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size)) );
        CUDA_TRY( cudaMemset(result_cols[i]->valid, 0, sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size)) );
    }
    for (int i = right_table_begin; i < result_num_cols; ++i) {
        gdf_column_view(result_cols[i], nullptr, nullptr, join_size, rnonjoincol[i - right_table_begin]->dtype);
        int col_width; get_column_byte_width(result_cols[i], &col_width);
        CUDA_TRY( cudaMalloc(&(result_cols[i]->data), col_width * join_size) );
        CUDA_TRY( cudaMalloc(&(result_cols[i]->valid), sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size)) );
        CUDA_TRY( cudaMemset(result_cols[i]->valid, 0, sizeof(gdf_valid_type)*gdf_get_num_chars_bitmask(join_size)) );
    }
    //create joined output column data buffers
    {
