[jira] [Comment Edited] (FLINK-6042) Display last n exceptions/causes for job restarts in Web UI

["Matthias (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-6042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17265799#comment-17265799 ] 

Matthias edited comment on FLINK-6042 at 1/15/21, 8:08 AM:
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{quote}Thanks for the proposal [~mapohl]. I have a few comments

1) When doing restarts with the new scheduler, then we will recreate the {{ExecutionGraph}}. Hence, exposing these error infos on the {{AccessExecutionGraph}} might not work.
{quote}
My plan was to not expose the {{ErrorInfo}} through {{ExecutionGraph}} but through {{ArchivedExecutionGraph}} which is a kind of serializable copy of {{ExecutionGraph}} and also implements {{AccessExecutionGraph}}. Restarting the {{ExecutionGraph}} shouldn't harm the {{ErrorInfo}} collection as it is held in the {{SchedulerNG}} implementation. The {{ErrorInfo}} collection would be used as an additional parameter when instantiating {{ArchivedExecutionGraph}} in [SchedulerBase.requestJob()|https://github.com/apache/flink/blob/ac968b83675e64712b4d35dbc166e09808c2156b/flink-runtime/src/main/java/org/apache/flink/runtime/scheduler/SchedulerBase.java#L800].

{quote}2) {{UpdateSchedulerNgOnInternalFailuresListener}} will only be called if an exception on the JM occurs. If there is a normal task failure, then we will call {{updateTaskExecutionState}}
{quote}
Thanks for the hint: {{SchedulerNG.updateTaskExecutionState(..)}} should work as well. This would then collect all the {{Exception}}s thrown in the different tasks. We could then utilize the {{JobStatusListener}} interface to identify the {{Exception}} that causes the job to restart and group all previously collected {{ErrorInfo}}s (that were not already assigned to a different root cause) under this root cause. Here, I'm not 100% sure, yet, whether triggering the consolidation of the {{ErrorInfo}}s works that easily.

{quote}3) It would be great to group the exceptions wrt to their restart cycles in the web UI. So seeing the root causes for a restart and then being able to expand the view to see the task failures for this specific restart would be awesome.
{quote}
The {{ErrorInfo}} groups mentioned in 2) could be then returned through the newly introduced access method described in 1) and forwarded by the {{JobExceptionsHandler}} to the web UI.


was (Author: mapohl):
{quote}Thanks for the proposal [~mapohl]. I have a few comments

1) When doing restarts with the new scheduler, then we will recreate the {{ExecutionGraph}}. Hence, exposing these error infos on the {{AccessExecutionGraph}} might not work.
{quote}
My plan was to not expose the {{ErrorInfo}} through {{ExecutionGraph}} but through {{ArchivedExecutionGraph}} which is a kind of serializable copy of {{ExecutionGraph}} and also implements {{AccessExecutionGraph}}. Restarting the {{ExecutionGraph}} shouldn't harm the {{ErrorInfo}} collection as it is held in the {{SchedulerNG}} implementation. The {{ErrorInfo}} collection would be used as an additional parameter when instantiating {{ArchivedExecutionGraph}} in [SchedulerBase.requestJob()|https://github.com/apache/flink/blob/ac968b83675e64712b4d35dbc166e09808c2156b/flink-runtime/src/main/java/org/apache/flink/runtime/scheduler/SchedulerBase.java#L800].

{quote}2) {{UpdateSchedulerNgOnInternalFailuresListener}} will only be called if an exception on the JM occurs. If there is a normal task failure, then we will call {{updateTaskExecutionState}}
{quote}
Thanks for the hint: {{SchedulerNG.updateTaskExecutionState(..)}} should work as well. This would then collect all the {{Exception}}s thrown in the different tasks. We could then utilize the {{JobStatusListener}} interface to identify the {{Exception}} that causes the job to restart and group all previously collected {{ErrorInfo}}s (that were not already assigned to a different root cause) under this root cause.

{quote}3) It would be great to group the exceptions wrt to their restart cycles in the web UI. So seeing the root causes for a restart and then being able to expand the view to see the task failures for this specific restart would be awesome.
{quote}
The {{ErrorInfo}} groups mentioned in 2) could be then returned through the newly introduced access method described in 1) and forwarded by the {{JobExceptionsHandler}} to the web UI.

> Display last n exceptions/causes for job restarts in Web UI
> -----------------------------------------------------------
>
>                 Key: FLINK-6042
>                 URL: https://issues.apache.org/jira/browse/FLINK-6042
>             Project: Flink
>          Issue Type: Improvement
>          Components: Runtime / Coordination, Runtime / Web Frontend
>    Affects Versions: 1.3.0
>            Reporter: Till Rohrmann
>            Assignee: Matthias
>            Priority: Major
>
> Users requested that it would be nice to see the last {{n}} exceptions causing a job restart in the Web UI. This will help to more easily debug and operate a job.
> We could store the root causes for failures similar to how prior executions are stored in the {{ExecutionVertex}} using the {{EvictingBoundedList}} and then serve this information via the Web UI.



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