ruanwenjun commented on a change in pull request #5572:
URL: https://github.com/apache/dolphinscheduler/pull/5572#discussion_r644788688
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File path:
dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/master/cache/impl/TaskInstanceCacheManagerImpl.java
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@@ -57,7 +86,7 @@
@Override
public TaskInstance getByTaskInstanceId(Integer taskInstanceId) {
TaskInstance taskInstance = taskInstanceCache.get(taskInstanceId);
Review comment:
@blackberrier
If there are two threads execute `getByTaskInstanceId` at the same time, we
just want to query from database once, right? The block will only happen on the
two thread update on the same key, and the key is not exist, this is expected.
And you should realize that the below way is not an atomic operation, in
some situation, it might cause problem.
```java
TaskInstance taskInstance = taskInstanceCache.get(taskInstanceId);
if (taskInstance == null){
taskInstance = processService.findTaskInstanceById(taskInstanceId);
taskInstanceCache.put(taskInstanceId,taskInstance);
}
return taskInstance;
```
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