Checkpoint is not triggering as per configuration

[syed]

Hi
I am new to the flink world, and trying to understand. Currently, I am using
Flink 1.3.2 on a small cluster of 4 nodes,
I have configured checkpoint directory at HDFS, and run streaming word count
example with my own custom input file of 63M entries,
I enabled checkpoint every one second {/env.enableCheckpointing(1000)/}

The problem I am facing is checkpoint is only triggered once after 1 second,
but no checkpoint afterwards, I run application for more than 5 minutes, but
checkpoint history shows only 1 checkpoint triggered and was successful. I
don't know why checkpoint not triggering after every second?
Please suggest me what is wrong?
Thanks in anticipation.




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

[Piotr Nowojski]

Hi,

Did you check task manager and job manager logs for any problems?

Piotrek

> On 5 Feb 2018, at 03:19, syed <[hidden email]> wrote:
>
> Hi
> I am new to the flink world, and trying to understand. Currently, I am using
> Flink 1.3.2 on a small cluster of 4 nodes,
> I have configured checkpoint directory at HDFS, and run streaming word count
> example with my own custom input file of 63M entries,
> I enabled checkpoint every one second {/env.enableCheckpointing(1000)/}
>
> The problem I am facing is checkpoint is only triggered once after 1 second,
> but no checkpoint afterwards, I run application for more than 5 minutes, but
> checkpoint history shows only 1 checkpoint triggered and was successful. I
> don't know why checkpoint not triggering after every second?
> Please suggest me what is wrong?
> Thanks in anticipation.
>
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[Piotr Nowojski]

Hi,

Please analyse what was going on the TaskManager and JobManager before this “task is not being executed at the moment”. What is the reason why it is not being executed? Was there some exception? Depending on your setup, you might need to check your stdout/stderr files (if your code is printing some errors).

Other issue might be if your operators/functions are initialising very slowly or being stuck somewhere.

Thanks, Piotrek

On 19 Mar 2018, at 10:14, ms110400027 Syed Muhammad Abrar Akber <[hidden email]> wrote:

Dear Piotrek;

The log for task manager shows the following message

2018-03-19 17:07:58,000 INFO  org.apache.flink.runtime.checkpoint.CheckpointCoordinator     - Checkpoint triggering task Source: Custom File Source (1/1) is not being executed at the moment. Aborting checkpoint.

I don't know how to fix this issue.  I will highly appreciate your support, if you help me in fixing the issue.

Further, please guide me where I can find the resources which are helpful for beginners like me to fix such issues.

Thank you for your support.

On Mon, Feb 5, 2018 at 5:33 PM, Piotr Nowojski <[hidden email]> wrote:

Hi,

Did you check task manager and job manager logs for any problems?

Piotrek

> On 5 Feb 2018, at 03:19, syed <[hidden email]> wrote:
>
> Hi
> I am new to the flink world, and trying to understand. Currently, I am using
> Flink 1.3.2 on a small cluster of 4 nodes,
> I have configured checkpoint directory at HDFS, and run streaming word count
> example with my own custom input file of 63M entries,
> I enabled checkpoint every one second {/env.enableCheckpointing(1000)/}
>
> The problem I am facing is checkpoint is only triggered once after 1 second,
> but no checkpoint afterwards, I run application for more than 5 minutes, but
> checkpoint history shows only 1 checkpoint triggered and was successful. I
> don't know why checkpoint not triggering after every second?
> Please suggest me what is wrong?
> Thanks in anticipation.
>
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[xiatao123]

I ran into a similar issue.

Since it is a "Custom File Source", the first source just listing
folder/file path for all existing files. Next operator "Split Reader" will
read the content of the file.  
"Custom File Source" went to "finished" state after first couple secs.
That's way we got this error message "Custom File Source (1/1) is not being
executed at the moment. Aborting checkpoint". Because the "Custom File
Source" finished already.

Is this by design?  Although the "Custom File Source" finished in secs, the
rest of the pipeline can running for hours or days. Whenever anything went
wrong, the pipeline will restart and start to reading from the beginning
again, since there is not any checkpoint.



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

[Piotr Nowojski]

Hi,

It’s not considered as a bug, only a missing not yet implemented feature (check my previous responses for the Jira ticket). Generally speaking using file input stream for DataStream programs is not very popular, thus this was so far low on our priority list.

Piotrek

> On 10 May 2018, at 06:26, xiatao123 <[hidden email]> wrote:
>
> I ran into a similar issue.
>
> Since it is a "Custom File Source", the first source just listing
> folder/file path for all existing files. Next operator "Split Reader" will
> read the content of the file.  
> "Custom File Source" went to "finished" state after first couple secs.
> That's way we got this error message "Custom File Source (1/1) is not being
> executed at the moment. Aborting checkpoint". Because the "Custom File
> Source" finished already.
>
> Is this by design?  Although the "Custom File Source" finished in secs, the
> rest of the pipeline can running for hours or days. Whenever anything went
> wrong, the pipeline will restart and start to reading from the beginning
> again, since there is not any checkpoint.
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[xiatao123]

Thanks for the reply Piotr. Which jira ticket were you refer to?

We were trying to use the same code for normal stream process to process very old historical backfill data.

The problem for me right now is that, backfill x years of data will be very slow. And I cannot have any checkpoint during the whole time since FileSource is "Finished". When anything goes wrong in the middle, the whole pipeline will start over from beginning again.

Anyway I can skip the checkpoint of "Source: Custom File Source" but still having checkpoint on "Split Reader: Custom File Source"?

Thanks,
Tao

On Fri, May 11, 2018 at 4:34 AM, Piotr Nowojski <[hidden email]> wrote:

Hi,

It’s not considered as a bug, only a missing not yet implemented feature (check my previous responses for the Jira ticket). Generally speaking using file input stream for DataStream programs is not very popular, thus this was so far low on our priority list.

Piotrek

> On 10 May 2018, at 06:26, xiatao123 <[hidden email]> wrote:
>
> I ran into a similar issue.
>
> Since it is a "Custom File Source", the first source just listing
> folder/file path for all existing files. Next operator "Split Reader" will
> read the content of the file. 
> "Custom File Source" went to "finished" state after first couple secs.
> That's way we got this error message "Custom File Source (1/1) is not being
> executed at the moment. Aborting checkpoint". Because the "Custom File
> Source" finished already.
>
> Is this by design?  Although the "Custom File Source" finished in secs, the
> rest of the pipeline can running for hours or days. Whenever anything went
> wrong, the pipeline will restart and start to reading from the beginning
> again, since there is not any checkpoint.
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[Piotr Nowojski]

Hi,

This one: https://issues.apache.org/jira/browse/FLINK-2491

1. What if you set `org.apache.flink.streaming.api.functions.source.FileProcessingMode#PROCESS_CONTINUOUSLY`? This will prevent split source from finishing, so checkpointing should work fine. Downside is that you would have to on your own, manually, determine whether the job has finished/completed or not.

Other things that come to my mind would require some coding:

2. Look at org.apache.flink.streaming.api.environment.StreamExecutionEnvironment#createFileInput, copy it’s code and replace `ContinuousFileMonitoringFunction` with something that finishes on some custom event/action/condition. The code that you would have to modify/replace is alongside usages of `FileProcessingMode monitoringMode`.

3. Probably even more complicated, you could modify ContinuousFileReaderOperator to be a source function, with statically precomputed list of files/splits to process (they would have to be assigned/distributed taking parallelism into account). Thus your source functions could complete not when splits are generated, but when they have finished reading splits.

Piotrek

On 14 May 2018, at 20:29, Tao Xia <[hidden email]> wrote:

Thanks for the reply Piotr. Which jira ticket were you refer to?

We were trying to use the same code for normal stream process to process very old historical backfill data.

The problem for me right now is that, backfill x years of data will be very slow. And I cannot have any checkpoint during the whole time since FileSource is "Finished". When anything goes wrong in the middle, the whole pipeline will start over from beginning again.

Anyway I can skip the checkpoint of "Source: Custom File Source" but still having checkpoint on "Split Reader: Custom File Source"?

Thanks,
Tao

On Fri, May 11, 2018 at 4:34 AM, Piotr Nowojski <[hidden email]> wrote:

Hi,

It’s not considered as a bug, only a missing not yet implemented feature (check my previous responses for the Jira ticket). Generally speaking using file input stream for DataStream programs is not very popular, thus this was so far low on our priority list.

Piotrek

> On 10 May 2018, at 06:26, xiatao123 <[hidden email]> wrote:
>
> I ran into a similar issue.
>
> Since it is a "Custom File Source", the first source just listing
> folder/file path for all existing files. Next operator "Split Reader" will
> read the content of the file. 
> "Custom File Source" went to "finished" state after first couple secs.
> That's way we got this error message "Custom File Source (1/1) is not being
> executed at the moment. Aborting checkpoint". Because the "Custom File
> Source" finished already.
>
> Is this by design?  Although the "Custom File Source" finished in secs, the
> rest of the pipeline can running for hours or days. Whenever anything went
> wrong, the pipeline will restart and start to reading from the beginning
> again, since there is not any checkpoint.
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[xiatao123]

Great, I will give a try.

Thanks,

Tao

On Tue, May 15, 2018 at 12:50 AM, Piotr Nowojski <[hidden email]> wrote:

Hi,

This one: https://issues.apache.org/jira/browse/FLINK-2491

1. What if you set `org.apache.flink.streaming.api.functions.source.FileProcessingMode#PROCESS_CONTINUOUSLY`? This will prevent split source from finishing, so checkpointing should work fine. Downside is that you would have to on your own, manually, determine whether the job has finished/completed or not.

Other things that come to my mind would require some coding:

2. Look at org.apache.flink.streaming.api.environment.StreamExecutionEnvironment#createFileInput, copy it’s code and replace `ContinuousFileMonitoringFunction` with something that finishes on some custom event/action/condition. The code that you would have to modify/replace is alongside usages of `FileProcessingMode monitoringMode`.

3. Probably even more complicated, you could modify ContinuousFileReaderOperator to be a source function, with statically precomputed list of files/splits to process (they would have to be assigned/distributed taking parallelism into account). Thus your source functions could complete not when splits are generated, but when they have finished reading splits.

Piotrek

On 14 May 2018, at 20:29, Tao Xia <[hidden email]> wrote:

Thanks for the reply Piotr. Which jira ticket were you refer to?

We were trying to use the same code for normal stream process to process very old historical backfill data.

The problem for me right now is that, backfill x years of data will be very slow. And I cannot have any checkpoint during the whole time since FileSource is "Finished". When anything goes wrong in the middle, the whole pipeline will start over from beginning again.

Anyway I can skip the checkpoint of "Source: Custom File Source" but still having checkpoint on "Split Reader: Custom File Source"?

Thanks,
Tao

On Fri, May 11, 2018 at 4:34 AM, Piotr Nowojski <[hidden email]> wrote:

Hi,

It’s not considered as a bug, only a missing not yet implemented feature (check my previous responses for the Jira ticket). Generally speaking using file input stream for DataStream programs is not very popular, thus this was so far low on our priority list.

Piotrek

> On 10 May 2018, at 06:26, xiatao123 <[hidden email]> wrote:
>
> I ran into a similar issue.
>
> Since it is a "Custom File Source", the first source just listing
> folder/file path for all existing files. Next operator "Split Reader" will
> read the content of the file. 
> "Custom File Source" went to "finished" state after first couple secs.
> That's way we got this error message "Custom File Source (1/1) is not being
> executed at the moment. Aborting checkpoint". Because the "Custom File
> Source" finished already.
>
> Is this by design?  Although the "Custom File Source" finished in secs, the
> rest of the pipeline can running for hours or days. Whenever anything went
> wrong, the pipeline will restart and start to reading from the beginning
> again, since there is not any checkpoint.
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/