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https://issues.apache.org/jira/browse/HIVE-18978?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Eugene Koifman reassigned HIVE-18978:
-------------------------------------
Assignee: Eugene Koifman
> ConditionalTask.addDependentTask(Task t) adds t in the wrong place
> ------------------------------------------------------------------
>
> Key: HIVE-18978
> URL: https://issues.apache.org/jira/browse/HIVE-18978
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Eugene Koifman
> Assignee: Eugene Koifman
> Priority: Major
>
> {{ConditionalTask.addDependentTask(Task t) }} is implemented like this:
> {noformat}
> /**
> * Add a dependent task on the current conditional task. The task will not be
> a direct child of
> * conditional task. Actually it will be added as child task of associated
> tasks.
> *
> * @return true if the task got added false if it already existed
> */
> @Override
> public boolean addDependentTask(Task<? extends Serializable> dependent) {
> boolean ret = false;
> if (getListTasks() != null) {
> ret = true;
> for (Task<? extends Serializable> tsk : getListTasks()) {
> ret = ret & tsk.addDependentTask(dependent);
> }
> }
> return ret;
> }
> {noformat}
> So let’s say, the tasks in the ConditionalTask are A,B,C, but they have
> children.
> {noformat}
> CondTask
> |--A
> |--A1
> |-A2
> |--B
> |--B1
> |--C
> |--C1
> {noformat}
> The way ConditionalTask.addDependent() is implemented, MyTask becomes a
> sibling of A1,
> B1 and C1. So even if only 1 branch of ConditionalTask is executed (and
> parallel task
> execution is enabled), there is no guarantee (as I see) that MyTask runs
> after A2 or
> B1 or C1, which is really what is needed.
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