keep add_column unchanged
keep add_column unchanged

apache/incubator-singa,apache/incubator-singa,apache/incubator-singa,nudles/incubator-singa,apache/incubator-singa,nudles/incubator-singa,nudles/incubator-singa,nudles/incubator-singa,apache/incubator-singa,nudles/incubator-singa