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123malin
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#### Required（必填, multiple choices, two at most）
- **PR type（PR 类型） is (C ):**
A. New features（新功能）---------------- D. Performance optimization（性能优化）
B. Bug fixes（问题修复）------------------ E. Breaking changes（向后不兼容的改变）
C. Function optimization（功能优化）------F.  Others（其它）

- **PR changes（改动点）is (D ):**
A. OPs（operators）---------------------- C. Docs（文档）
B. APIs（接口）--------------------------- D. Others（其它）

- **Use one sentence to describe what this PR does.（简述本次PR的目的和改动）**
给downpour_worker.cc增加try_catch机制，op执行发生异常的时候打印program所有参数，方便调试、定位问题。

-----------------------
#### Optional（选填, If None, please delete it）

- **Describe what this PR does in detail. If this PR fixes an issue, please give the issue id.**
  <!-- DESCRIBE THE BUG OR REQUIREMENT HERE. eg. #2020（格式为 #Issue编号）-->

- **If you modified docs, please make sure that both Chinese and English docs were modified and provide a preview screenshot. （文档必填）**
   <!-- ADD SCREENSHOT HERE IF APPLICABLE. -->

- **Please write down other information you want to tell reviewers.**
downpour_worker增加try_catch机制，打印program所有参数
issue