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Posted to issues@flink.apache.org by "Fabian Hueske (JIRA)" <ji...@apache.org> on 2018/06/05 10:20:00 UTC
[jira] [Assigned] (FLINK-9524) NPE from
ProcTimeBoundedRangeOver.scala
[ https://issues.apache.org/jira/browse/FLINK-9524?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Fabian Hueske reassigned FLINK-9524:
------------------------------------
Assignee: yan zhou
> NPE from ProcTimeBoundedRangeOver.scala
> ---------------------------------------
>
> Key: FLINK-9524
> URL: https://issues.apache.org/jira/browse/FLINK-9524
> Project: Flink
> Issue Type: Bug
> Components: Table API & SQL
> Affects Versions: 1.5.0
> Reporter: yan zhou
> Assignee: yan zhou
> Priority: Major
> Attachments: npe_from_ProcTimeBoundedRangeOver.txt
>
>
> The class _ProcTimeBoundedRangeOver_ would throws NPE if _minRetentionTime_ and _maxRetentionTime_ are set to greater then 1.
> Please see [^npe_from_ProcTimeBoundedRangeOver.txt] for the detail of exception. Below is a short description of the cause:
> * When the first event for a key arrives, the cleanup time is registered with _timerservice_ and recorded in _cleanupTimeState_. If the second event with same key arrives before the cleanup time, the value in _cleanupTimeState_ is updated and a new timer is registered to _timerService_. So now we have two registered timers for cleanup. One is registered because of the first event, the other for the second event.
> * However, when _onTimer_ method is fired for the first cleanup timer, the _cleanupTimeStates_ value has already been updated to second cleanup time. So it will bypass the _needToCleanupState_ check, and yet run through the remained code of _onTimer_ (which is intended to update the accumulator and emit output) and cause NPE.
> _RowTimeBoundedRangeOver_ has very similar logic with _ProcTimeBoundedRangeOver. But_ It won't cause NPE by the same reason. To avoid the exception, it simply add a null check before running the logic for updating accumulator.
>
>
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