add debug info

recommend-model-produce/src/main/python/models/dssm/bq_reader_train_ps.py

@@ -13,6 +13,7 @@ class DSSMReader(MultiSlotDataGenerator):
     def line_process(self, line):
         try:
             # 按tab分割样本的各个字段
+            sys.stderr.write(f"processing line: {line}")
             sample_values = line.rstrip('\n').split('\t')
             if len(sample_values) == 6: # 训练格式
                 sample_id, label, vid_left,vid_right,left_features, right_features = sample_values