Going through the release notes today - we tried fiddling with the
taskmanager.memory.fraction option, going as low as 0.1 with unfortunately no
success. It still leads to the container running beyond physical memory limits.
// ah
From: Hailu, Andreas [Engineering]
Sent: Tuesday, November 19, 2019 6:01 PM
To: 'user@flink.apache.org' <user@flink.apache.org>
Subject: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
Hi,
We're in the middle of testing the upgrade of our data processing flows from
Flink 1.6.4 to 1.9.1. We're seeing that flows which were running just fine on
1.6.4 now fail on 1.9.1 with the same application resources and input data
size. It seems that there have been some changes around how the data is sorted
prior to being fed to the CoGroup operator - this is the error that we
encounter:
Caused by: org.apache.flink.runtime.client.JobExecutionException: Job execution
failed.
at
org.apache.flink.runtime.jobmaster.JobResult.toJobExecutionResult(JobResult.java:146)
at
org.apache.flink.client.program.rest.RestClusterClient.submitJob(RestClusterClient.java:259)
... 15 more
Caused by: java.lang.Exception: The data preparation for task 'CoGroup (Dataset
| Merge | NONE)' , caused an error: Error obtaining the sorted input: Thread
'SortMerger Reading Thread' terminated due to an exception: Lost connection to
task manager 'd73996-213.dc.gs.com/10.47.226.218:46003'. This indicates that
the remote task manager was lost.
at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:480)
at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:369)
at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:705)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:530)
... 1 more
Caused by: java.lang.RuntimeException: Error obtaining the sorted input: Thread
'SortMerger Reading Thread' terminated due to an exception: Lost connection to
task manager 'd73996-213.dc.gs.com/10.47.226.218:46003'. This indicates that
the remote task manager was lost.
at
org.apache.flink.runtime.operators.sort.UnilateralSortMerger.getIterator(UnilateralSortMerger.java:650)
at org.apache.flink.runtime.operators.BatchTask.getInput(BatchTask.java:1109)
at
org.apache.flink.runtime.operators.CoGroupDriver.prepare(CoGroupDriver.java:102)
at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:474)
I drilled further down into the YARN app logs, and I found that the container
was running out of physical memory:
2019-11-19 12:49:23,068 INFO org.apache.flink.yarn.YarnResourceManager
- Closing TaskExecutor connection
container_e42_1574076744505_9444_01_000004 because: Container
[pid=42774,containerID=container_e42_1574076744505_9444_01_000004] is running
beyond physical memory limits. Current usage: 12.0 GB of 12 GB physical memory
used; 13.9 GB of 25.2 GB virtual memory used. Killing container.
This is what leads my suspicions as this resourcing configuration worked just
fine on 1.6.4
I'm working on getting heap dumps of these applications to try and get a better
understanding of what's causing the blowup in physical memory required myself,
but it would be helpful if anyone knew what relevant changes have been made
between these versions or where else I could look? There are some features in
1.9 that we'd like to use in our flows so getting this sorted out, no pun
intended, is inhibiting us from doing so.
Best,
Andreas
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