Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Piotr Nowojski]

Hi,

Yes, it is only related to **batch** jobs, but not necessarily only to DataSet 
API jobs. If you are using for example Blink SQL/Table API to process some 
bounded data streams (tables), it could also be visible/affected there. If not, 
I would suggest to start a new user mailing list question and posting the 
details (what are you running, job manager/task manager logs, …).

Piotrek

> On 2 Dec 2019, at 10:51, Victor Wong  wrote:
> 
> Hi,
> 
> We encountered similar issues that the task manager kept being killed by yarn.
> 
> - flink 1.9.1
> - heap usage is low.
> 
> But our job is a **streaming** job, so I want to ask if this issue is only 
> related to **batch** job or not? Thanks!
> 
> Best,
> Victor
> 
> 
> yingjie mailto:yjclove...@gmail.com>> 于2019年11月28日周四 
> 上午11:43写道：
> Piotr is right, that depend on the data size you are reading and the memory
> pressure. Those memory occupied by mmapped region can be recycled and used
> by other processes if memory pressure is high, that is, other process or
> service on the same node won't be affected because the OS will recycle the
> mmapped pages if needed. But currently, you can't assume a bound of the
> memory can be used, because it will use more memory as long as there is free
> space and you have more new data to read.
> 
> 
> 
> --
> Sent from: 
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/ 
> 
> 
> 
> -- 
> 
> Best,
> Victor

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Victor Wong]

Hi,

We encountered similar issues that the task manager kept being killed by
yarn.

- flink 1.9.1
- heap usage is low.

But our job is a **streaming** job, so I want to ask if this issue is only
related to **batch** job or not? Thanks!

Best,
Victor


yingjie  于2019年11月28日周四 上午11:43写道：

> Piotr is right, that depend on the data size you are reading and the memory
> pressure. Those memory occupied by mmapped region can be recycled and used
> by other processes if memory pressure is high, that is, other process or
> service on the same node won't be affected because the OS will recycle the
> mmapped pages if needed. But currently, you can't assume a bound of the
> memory can be used, because it will use more memory as long as there is
> free
> space and you have more new data to read.
>
>
>
> --
> Sent from:
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/
>


-- 

Best,
Victor

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[yingjie]

Piotr is right, that depend on the data size you are reading and the memory
pressure. Those memory occupied by mmapped region can be recycled and used
by other processes if memory pressure is high, that is, other process or
service on the same node won't be affected because the OS will recycle the
mmapped pages if needed. But currently, you can't assume a bound of the
memory can be used, because it will use more memory as long as there is free
space and you have more new data to read.



--
Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Piotr Nowojski]

Hi,

> @yingjie   Do you have any idea how much memory will be stolen from OS when 
> using mmap for data reading?

I think this is bounded only by the size of the written data. Also it will not 
be “stolen from OS”, as kernel is controlling the amount of pages residing 
currently in the RAM depending on the current memory pressure (the same was as 
file cache).

Piotrek
  
> On 27 Nov 2019, at 04:50, bupt_ljy  wrote:
> 
> Hi,
> 
> I’ve met the exactly same problem recently and solved it in Piotr’s way. 
> @zhijiang, I didn’t see any oom error thrown by JVM (I’m not sure this can be 
> thrown if yarn decides to kill it in a mandatory way). According to our 
> monitoring system, the overusage of memory is from JVM directy memory.
> 
> The interesting part is that the old way works if I increase the 
> -XX:MaxDirectMemorySize to be around 3 GB (it’s around 2GB before). So I 
> suspect we at least need to reserve one #ByteBuffer’s size in 
> #memoryMappedRegions for #MappedByteBuffer (which is 2 GB for large files). 
> Not sure I’m right about this.
> 
> @yingjie   Do you have any idea how much memory will be stolen from OS when 
> using mmap for data reading?
> 
> 
> Best,
> Jiayi Liao
> 
>  Original Message 
> Sender: yingjie
> Recipient: user
> Date: Tuesday, Nov 26, 2019 18:10
> Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
> 
> The new BlockingSubpartition implementation in 1.9 uses mmap for data reading
> by default which means it steals memory from OS. The mmaped region memory is
> managed by JVM, so there should be no OutOfMemory problem reported by JVM
> and the OS memory is also not exhausted, so there should be no kernal OOM.
> I think Piotr's suspicion is right, yarn tracked the memory used and killed
> the TM (the mmap region is also part of the process memory).
> 
> Giving a strict resource restriction to the container (larger than the yarn
> limit) which can avoid memory steal or using file instead of mmap as pointed
> out by Piotr can solve the problem.
> 
> I think Flink may need to restrict the amount of memory can be stolen.
> 
> 
> 
> --
> Sent from: 
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/ 
> <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/>

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[bupt_ljy]

Hi,


I’ve met the exactly same problem recently and solved it in Piotr’s way. 
@zhijiang, I didn’t see any oom error thrown by JVM (I’m not sure this can be 
thrown if yarn decides to kill it in a mandatory way). According to our 
monitoring system, the overusage of memory is from JVM directy memory.


The interesting part is that the old way works if I increase the 
-XX:MaxDirectMemorySize to be around 3 GB (it’s around 2GB before). So I 
suspect we at least need to reserve one #ByteBuffer’s size in 
#memoryMappedRegions for #MappedByteBuffer (which is 2 GB for large files). Not 
sure I’m right about this.


@yingjie   Do you have any idea how much memory will be stolen from OS when 
using mmap for data reading?




Best,
Jiayi Liao


 Original Message 
Sender: yingjie
Recipient: user
Date: Tuesday, Nov 26, 2019 18:10
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?


The new BlockingSubpartition implementation in 1.9 uses mmap for data reading 
by default which means it steals memory from OS. The mmaped region memory is 
managed by JVM, so there should be no OutOfMemory problem reported by JVM and 
the OS memory is also not exhausted, so there should be no kernal OOM. I think 
Piotr's suspicion is right, yarn tracked the memory used and killed the TM (the 
mmap region is also part of the process memory). Giving a strict resource 
restriction to the container (larger than the yarn limit) which can avoid 
memory steal or using file instead of mmap as pointed out by Piotr can solve 
the problem. I think Flink may need to restrict the amount of memory can be 
stolen. -- Sent from: 
http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Piotr Nowojski]

Thanks for the confirmation, I’ve created Jira ticket to track this issue [1]

https://issues.apache.org/jira/browse/FLINK-14952 


Piotrek

> On 26 Nov 2019, at 11:10, yingjie  wrote:
> 
> The new BlockingSubpartition implementation in 1.9 uses mmap for data reading
> by default which means it steals memory from OS. The mmaped region memory is
> managed by JVM, so there should be no OutOfMemory problem reported by JVM
> and the OS memory is also not exhausted, so there should be no kernal OOM.
> I think Piotr's suspicion is right, yarn tracked the memory used and killed
> the TM (the mmap region is also part of the process memory).
> 
> Giving a strict resource restriction to the container (larger than the yarn
> limit) which can avoid memory steal or using file instead of mmap as pointed
> out by Piotr can solve the problem.
> 
> I think Flink may need to restrict the amount of memory can be stolen.
> 
> 
> 
> --
> Sent from: 
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[yingjie]

The new BlockingSubpartition implementation in 1.9 uses mmap for data reading
by default which means it steals memory from OS. The mmaped region memory is
managed by JVM, so there should be no OutOfMemory problem reported by JVM
and the OS memory is also not exhausted, so there should be no kernal OOM.
I think Piotr's suspicion is right, yarn tracked the memory used and killed
the TM (the mmap region is also part of the process memory).

Giving a strict resource restriction to the container (larger than the yarn
limit) which can avoid memory steal or using file instead of mmap as pointed
out by Piotr can solve the problem.

I think Flink may need to restrict the amount of memory can be stolen.



--
Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Piotr Nowojski]

Hi,

Good to hear that you were able to workaround the problem.

I’m not sure what’s the exact reason why mmaped partitions caused those 
failures, but you are probably right that they have caused some memory 
exhaustion. Probably this memory is not capped by anything, but I would expect 
kernel to release it instead of killing the container, unless this was not 
kernel’s OOM killer that killed the container. Is that what’s happening? Yarn 
is keeping track of the used memory and Flink’s mmap files unbounded usage of 
mmap files caused to exceed this limit?

I’ve asked some colleagues to take a look here, but most of them are busy this 
week with Flink Forward Asia, so they might not respond immediately.

Piotrek

> On 22 Nov 2019, at 14:51, Hailu, Andreas  wrote:
> 
> Zhijiang, Piotr, we made this change and it solved our mmap usage problem, so 
> we can move forward in our testing. Thanks.
>  
> I’m curious – if I’m understanding this change in 1.9 correctly, blocking 
> result partitions were being written to mmap which in turn resulted in 
> exhausting container memory? This is why we were seeing failures in our 
> pipelines which had operators which fed into a CoGroup?
>  
> // ah
>  
>  <>From: Zhijiang  
> Sent: Thursday, November 21, 2019 9:48 PM
> To: Hailu, Andreas [Engineering] ; Piotr 
> Nowojski 
> Cc: user@flink.apache.org
> Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> The hint of mmap usage below is really helpful to locate this problem. I 
> forgot this biggest change for batch job in release-1.9.
> The blocking type option can be set to `file` as Piotr suggested to behave 
> similar as before. I think it can solve your problem. 
>  
> --
> From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
> Send Time:2019 Nov. 21 (Thu.) 23:37
> To:Piotr Nowojski mailto:pi...@ververica.com>>
> Cc:Zhijiang mailto:wangzhijiang...@aliyun.com>>; 
> user@flink.apache.org <mailto:user@flink.apache.org>  <mailto:user@flink.apache.org>>
> Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> Thanks, Piotr. We’ll rerun our apps today with this and get back to you.
>  
> // ah
>  
> From: Piotr Nowojski  <mailto:pi...@data-artisans.com>> On Behalf Of Piotr Nowojski
> Sent: Thursday, November 21, 2019 10:14 AM
> To: Hailu, Andreas [Engineering]  <mailto:andreas.ha...@ny.email.gs.com>>
> Cc: Zhijiang  <mailto:wangzhijiang...@aliyun.com>>; user@flink.apache.org 
> <mailto:user@flink.apache.org>
> Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> Hi,
>  
> I would suspect this:
> https://issues.apache.org/jira/browse/FLINK-12070 
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__issues.apache.org_jira_browse_FLINK-2D12070&d=DwMFaQ&c=7563p3e2zaQw0AB1wrFVgyagb2IE5rTZOYPxLxfZlX4&r=hRr4SA7BtUvKoMBP6VDhfisy2OJ1ZAzai-pcCC6TFXM&m=pNSp_BPfgPubdHs-ZksQEfyjw6CMnhZ9_Jyb9_iD0VE&s=KWvzvfmJkcvcfiK-HlfNJeslBFOgnJtoHsZfMNtLoSo&e=>
> To be the source of the problems.
>  
> There seems to be a hidden configuration option that avoids using memory 
> mapped files:
>  
> taskmanager.network.bounded-blocking-subpartition-type: file
>  
> Could you test if helps?
>  
> Piotrek
>  
> 
> On 21 Nov 2019, at 15:22, Hailu, Andreas  <mailto:andreas.ha...@gs.com>> wrote:
>  
> Hi Zhijiang,
>  
> I looked into the container logs for the failure, and didn’t see any specific 
> OutOfMemory errors before it was killed. I ran the application using the same 
> config this morning on 1.6.4, and it went through successfully. I took a 
> snapshot of the memory usage from the dashboard and can send it to you if you 
> like for reference.
>  
> What stands out to me as suspicious is that on 1.9.1, the application is 
> using nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 
> throughout its runtime and succeeds. The JVM heap memory itself never exceeds 
> its capacity, peaking at 6.65GB, so it sounds like the problem lies somewhere 
> in the changes around mapped memory.
>  
> // ah
>  
> From: Zhijiang  <mailto:wangzhijiang...@aliyun.com>> 
> Sent: Wednesday, November 20, 2019 11:32 PM
> To: Hailu, Andreas [Engineering]  <mailto:andreas.ha...@ny.email.gs.com>>; user@flink.apache.org 
> <mailto:user@flink.apache.org>
> Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> Hi Andreas,
>  
> You are running a batch job, so there should be no native memory used by 
> rocked state backend. Then I guess it is either heap memory or direct memory 
> over used. Th

RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Hailu, Andreas]

Zhijiang, Piotr, we made this change and it solved our mmap usage problem, so 
we can move forward in our testing. Thanks.

I’m curious – if I’m understanding this change in 1.9 correctly, blocking 
result partitions were being written to mmap which in turn resulted in 
exhausting container memory? This is why we were seeing failures in our 
pipelines which had operators which fed into a CoGroup?

// ah

From: Zhijiang 
Sent: Thursday, November 21, 2019 9:48 PM
To: Hailu, Andreas [Engineering] ; Piotr 
Nowojski 
Cc: user@flink.apache.org
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

The hint of mmap usage below is really helpful to locate this problem. I forgot 
this biggest change for batch job in release-1.9.
The blocking type option can be set to `file` as Piotr suggested to behave 
similar as before. I think it can solve your problem.

--
From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
Send Time:2019 Nov. 21 (Thu.) 23:37
To:Piotr Nowojski mailto:pi...@ververica.com>>
Cc:Zhijiang mailto:wangzhijiang...@aliyun.com>>; 
user@flink.apache.org<mailto:user@flink.apache.org> 
mailto:user@flink.apache.org>>
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Thanks, Piotr. We’ll rerun our apps today with this and get back to you.

// ah

From: Piotr Nowojski mailto:pi...@data-artisans.com>> 
On Behalf Of Piotr Nowojski
Sent: Thursday, November 21, 2019 10:14 AM
To: Hailu, Andreas [Engineering] 
mailto:andreas.ha...@ny.email.gs.com>>
Cc: Zhijiang mailto:wangzhijiang...@aliyun.com>>; 
user@flink.apache.org<mailto:user@flink.apache.org>
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Hi,

I would suspect this:
https://issues.apache.org/jira/browse/FLINK-12070<https://urldefense.proofpoint.com/v2/url?u=https-3A__issues.apache.org_jira_browse_FLINK-2D12070&d=DwMFaQ&c=7563p3e2zaQw0AB1wrFVgyagb2IE5rTZOYPxLxfZlX4&r=hRr4SA7BtUvKoMBP6VDhfisy2OJ1ZAzai-pcCC6TFXM&m=pNSp_BPfgPubdHs-ZksQEfyjw6CMnhZ9_Jyb9_iD0VE&s=KWvzvfmJkcvcfiK-HlfNJeslBFOgnJtoHsZfMNtLoSo&e=>
To be the source of the problems.

There seems to be a hidden configuration option that avoids using memory mapped 
files:

taskmanager.network.bounded-blocking-subpartition-type: file

Could you test if helps?

Piotrek

On 21 Nov 2019, at 15:22, Hailu, Andreas 
mailto:andreas.ha...@gs.com>> wrote:

Hi Zhijiang,

I looked into the container logs for the failure, and didn’t see any specific 
OutOfMemory errors before it was killed. I ran the application using the same 
config this morning on 1.6.4, and it went through successfully. I took a 
snapshot of the memory usage from the dashboard and can send it to you if you 
like for reference.

What stands out to me as suspicious is that on 1.9.1, the application is using 
nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 throughout its 
runtime and succeeds. The JVM heap memory itself never exceeds its capacity, 
peaking at 6.65GB, so it sounds like the problem lies somewhere in the changes 
around mapped memory.

// ah

From: Zhijiang mailto:wangzhijiang...@aliyun.com>>
Sent: Wednesday, November 20, 2019 11:32 PM
To: Hailu, Andreas [Engineering] 
mailto:andreas.ha...@ny.email.gs.com>>; 
user@flink.apache.org<mailto:user@flink.apache.org>
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Hi Andreas,

You are running a batch job, so there should be no native memory used by rocked 
state backend. Then I guess it is either heap memory or direct memory over 
used. The heap managed memory is mainly used by batch operators and direct 
memory is used by network shuffle. Can you further check whether there are any 
logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? If the 
used memory exceeds the JVM configuration, it should throw that error. Then we 
can further narrow down the scope. I can not remember the changes of memory 
issues for managed memory or network stack, especially it really spans several 
releases.

Best,
Zhijiang

--
From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
Send Time:2019 Nov. 21 (Thu.) 01:03
To:user@flink.apache.org<mailto:user@flink.apache.org> 
mailto:user@flink.apache.org>>
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

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<mailto:user@flink.apache.org>' 
mailto:user@flink.apache.org>>
Subject: CoGroup SortMerger performance degrada

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Zhijiang]

The hint of mmap usage below is really helpful to locate this problem. I forgot 
this biggest change for batch job in release-1.9.
The blocking type option can be set to `file` as Piotr suggested to behave 
similar as before. I think it can solve your problem. 


--
From:Hailu, Andreas 
Send Time:2019 Nov. 21 (Thu.) 23:37
To:Piotr Nowojski 
Cc:Zhijiang ; user@flink.apache.org 

Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Thanks, Piotr. We’ll rerun our apps today with this and get back to you. 

// ah

From: Piotr Nowojski  On Behalf Of Piotr Nowojski
Sent: Thursday, November 21, 2019 10:14 AM
To: Hailu, Andreas [Engineering] 
Cc: Zhijiang ; user@flink.apache.org
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
Hi,
I would suspect this:
https://issues.apache.org/jira/browse/FLINK-12070
To be the source of the problems.
There seems to be a hidden configuration option that avoids using memory mapped 
files:
taskmanager.network.bounded-blocking-subpartition-type: file
Could you test if helps?
Piotrek



On 21 Nov 2019, at 15:22, Hailu, Andreas  wrote:
Hi Zhijiang,

I looked into the container logs for the failure, and didn’t see any specific 
OutOfMemory errors before it was killed. I ran the application using the same 
config this morning on 1.6.4, and it went through successfully. I took a 
snapshot of the memory usage from the dashboard and can send it to you if you 
like for reference.

What stands out to me as suspicious is that on 1.9.1, the application is using 
nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 throughout its 
runtime and succeeds. The JVM heap memory itself never exceeds its capacity, 
peaking at 6.65GB, so it sounds like the problem lies somewhere in the changes 
around mapped memory.

// ah

From: Zhijiang  
Sent: Wednesday, November 20, 2019 11:32 PM
To: Hailu, Andreas [Engineering] ; 
user@flink.apache.org
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
Hi Andreas,

You are running a batch job, so there should be no native memory used by rocked 
state backend. Then I guess it is either heap memory or direct memory over 
used. The heap managed memory is mainly used by batch operators and direct 
memory is used by network shuffle. Can you further check whether there are any 
logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? If the 
used memory exceeds the JVM configuration, it should throw that error. Then we 
can further narrow down the scope. I can not remember the changes of memory 
issues for managed memory or network stack, especially it really spans several 
releases.

Best,
Zhijiang

--
From:Hailu, Andreas 
Send Time:2019 Nov. 21 (Thu.) 01:03
To:user@flink.apache.org 
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

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' 
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'

RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Hailu, Andreas]

Thanks, Piotr. We’ll rerun our apps today with this and get back to you.

// ah

From: Piotr Nowojski  On Behalf Of Piotr Nowojski
Sent: Thursday, November 21, 2019 10:14 AM
To: Hailu, Andreas [Engineering] 
Cc: Zhijiang ; user@flink.apache.org
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Hi,

I would suspect this:
https://issues.apache.org/jira/browse/FLINK-12070<https://urldefense.proofpoint.com/v2/url?u=https-3A__issues.apache.org_jira_browse_FLINK-2D12070&d=DwMFaQ&c=7563p3e2zaQw0AB1wrFVgyagb2IE5rTZOYPxLxfZlX4&r=hRr4SA7BtUvKoMBP6VDhfisy2OJ1ZAzai-pcCC6TFXM&m=pNSp_BPfgPubdHs-ZksQEfyjw6CMnhZ9_Jyb9_iD0VE&s=KWvzvfmJkcvcfiK-HlfNJeslBFOgnJtoHsZfMNtLoSo&e=>
To be the source of the problems.

There seems to be a hidden configuration option that avoids using memory mapped 
files:

taskmanager.network.bounded-blocking-subpartition-type: file

Could you test if helps?

Piotrek


On 21 Nov 2019, at 15:22, Hailu, Andreas 
mailto:andreas.ha...@gs.com>> wrote:

Hi Zhijiang,

I looked into the container logs for the failure, and didn’t see any specific 
OutOfMemory errors before it was killed. I ran the application using the same 
config this morning on 1.6.4, and it went through successfully. I took a 
snapshot of the memory usage from the dashboard and can send it to you if you 
like for reference.

What stands out to me as suspicious is that on 1.9.1, the application is using 
nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 throughout its 
runtime and succeeds. The JVM heap memory itself never exceeds its capacity, 
peaking at 6.65GB, so it sounds like the problem lies somewhere in the changes 
around mapped memory.

// ah

From: Zhijiang mailto:wangzhijiang...@aliyun.com>>
Sent: Wednesday, November 20, 2019 11:32 PM
To: Hailu, Andreas [Engineering] 
mailto:andreas.ha...@ny.email.gs.com>>; 
user@flink.apache.org<mailto:user@flink.apache.org>
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Hi Andreas,

You are running a batch job, so there should be no native memory used by rocked 
state backend. Then I guess it is either heap memory or direct memory over 
used. The heap managed memory is mainly used by batch operators and direct 
memory is used by network shuffle. Can you further check whether there are any 
logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? If the 
used memory exceeds the JVM configuration, it should throw that error. Then we 
can further narrow down the scope. I can not remember the changes of memory 
issues for managed memory or network stack, especially it really spans several 
releases.

Best,
Zhijiang

--
From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
Send Time:2019 Nov. 21 (Thu.) 01:03
To:user@flink.apache.org<mailto:user@flink.apache.org> 
mailto:user@flink.apache.org>>
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

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<mailto:user@flink.apache.org>' 
mailto: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<http://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: Erro

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Piotr Nowojski]

Hi,

I would suspect this:
https://issues.apache.org/jira/browse/FLINK-12070 
<https://issues.apache.org/jira/browse/FLINK-12070>
To be the source of the problems.

There seems to be a hidden configuration option that avoids using memory mapped 
files:

taskmanager.network.bounded-blocking-subpartition-type: file

Could you test if helps?

Piotrek

> On 21 Nov 2019, at 15:22, Hailu, Andreas  wrote:
> 
> Hi Zhijiang,
>  
> I looked into the container logs for the failure, and didn’t see any specific 
> OutOfMemory errors before it was killed. I ran the application using the same 
> config this morning on 1.6.4, and it went through successfully. I took a 
> snapshot of the memory usage from the dashboard and can send it to you if you 
> like for reference.
>  
> What stands out to me as suspicious is that on 1.9.1, the application is 
> using nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 
> throughout its runtime and succeeds. The JVM heap memory itself never exceeds 
> its capacity, peaking at 6.65GB, so it sounds like the problem lies somewhere 
> in the changes around mapped memory.
>  
> // ah
>  
>  <>From: Zhijiang  
> Sent: Wednesday, November 20, 2019 11:32 PM
> To: Hailu, Andreas [Engineering] ; 
> user@flink.apache.org
> Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> Hi Andreas,
>  
> You are running a batch job, so there should be no native memory used by 
> rocked state backend. Then I guess it is either heap memory or direct memory 
> over used. The heap managed memory is mainly used by batch operators and 
> direct memory is used by network shuffle. Can you further check whether there 
> are any logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? 
> If the used memory exceeds the JVM configuration, it should throw that error. 
> Then we can further narrow down the scope. I can not remember the changes of 
> memory issues for managed memory or network stack, especially it really spans 
> several releases.
>  
> Best,
> Zhijiang
>  
> --
> From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
> Send Time:2019 Nov. 21 (Thu.) 01:03
> To:user@flink.apache.org  <mailto:user@flink.apache.org>>
> Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?
>  
> 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'  <mailto: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.oper

RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Hailu, Andreas]

Hi Zhijiang,

I looked into the container logs for the failure, and didn’t see any specific 
OutOfMemory errors before it was killed. I ran the application using the same 
config this morning on 1.6.4, and it went through successfully. I took a 
snapshot of the memory usage from the dashboard and can send it to you if you 
like for reference.

What stands out to me as suspicious is that on 1.9.1, the application is using 
nearly 6GB of Mapped memory before it dies, while 1.6.4 uses 0 throughout its 
runtime and succeeds. The JVM heap memory itself never exceeds its capacity, 
peaking at 6.65GB, so it sounds like the problem lies somewhere in the changes 
around mapped memory.

// ah

From: Zhijiang 
Sent: Wednesday, November 20, 2019 11:32 PM
To: Hailu, Andreas [Engineering] ; 
user@flink.apache.org
Subject: Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

Hi Andreas,

You are running a batch job, so there should be no native memory used by rocked 
state backend. Then I guess it is either heap memory or direct memory over 
used. The heap managed memory is mainly used by batch operators and direct 
memory is used by network shuffle. Can you further check whether there are any 
logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? If the 
used memory exceeds the JVM configuration, it should throw that error. Then we 
can further narrow down the scope. I can not remember the changes of memory 
issues for managed memory or network stack, especially it really spans several 
releases.

Best,
Zhijiang

--
From:Hailu, Andreas mailto:andreas.ha...@gs.com>>
Send Time:2019 Nov. 21 (Thu.) 01:03
To:user@flink.apache.org mailto:user@flink.apache.org>>
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

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' 
mailto: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_04 because: Container 
[pid=42774,containerID=container_e42_1574076744505_9444_01_04] 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 a

Re: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Zhijiang]

Hi Andreas,

You are running a batch job, so there should be no native memory used by rocked 
state backend. Then I guess it is either heap memory or direct memory over 
used. The heap managed memory is mainly used by batch operators and direct 
memory is used by network shuffle. Can you further check whether there are any 
logs to indicate HeapOutOfMemory or DirectOutOfMemory before killed? If the 
used memory exceeds the JVM configuration, it should throw that error. Then we 
can further narrow down the scope. I can not remember the changes of memory 
issues for managed memory or network stack, especially it really spans several 
releases.

Best,
Zhijiang


--
From:Hailu, Andreas 
Send Time:2019 Nov. 21 (Thu.) 01:03
To:user@flink.apache.org 
Subject:RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

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' 
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_04 because: Container 
[pid=42774,containerID=container_e42_1574076744505_9444_01_04] 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

 Your Personal Data: We may collect and process information about you that may 
be subject to data protection laws. For more information about how we use and 
disclose your personal data, how we protect your information, our legal basis 
to use your information, your rights and who you can contact, please refer to:  
www.gs.com/privacy-notices

RE: CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Hailu, Andreas]

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' 
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_04 because: Container 
[pid=42774,containerID=container_e42_1574076744505_9444_01_04] 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



Your Personal Data: We may collect and process information about you that may 
be subject to data protection laws. For more information about how we use and 
disclose your personal data, how we protect your information, our legal basis 
to use your information, your rights and who you can contact, please refer to: 
www.gs.com/privacy-notices<http://www.gs.com/privacy-notices>

CoGroup SortMerger performance degradation from 1.6.4 - 1.9.1?

[Hailu, Andreas]

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_04 because: Container 
[pid=42774,containerID=container_e42_1574076744505_9444_01_04] 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



Your Personal Data: We may collect and process information about you that may 
be subject to data protection laws. For more information about how we use and 
disclose your personal data, how we protect your information, our legal basis 
to use your information, your rights and who you can contact, please refer to: 
www.gs.com/privacy-notices