Fwd: Question about flink checkpoint

[Chengzhi Zhao]

Hey, I am new to flink and I have a question and want to see if anyone can help here.

So we have a s3 path that flink is monitoring that path to see new files available.

val avroInputStream_activity = env.readFile(format, path, FileProcessingMode.PROCESS_CONTINUOUSLY, 10000)  

I am doing both internal and external check pointing and let's say there is a bad file came to the path and flink will do several retries. I want to take those bad files and let the process continue. However, since the file path persist in the checkpoint, when I try to resume from external checkpoint, it threw the following error on no file been found.

java.io.IOException: Error opening the Input Split s3a://myfile [0,904]: No such file or directory: s3a://myfile

Is there a way to skip this bad file and move on? 

Thanks in advance.

Best,

Chengzhi Zhao

[Fabian Hueske-2]

Hi Chengzhi Zhao,

I think this is rather an issue with the ContinuousFileReaderOperator than with the checkpointing algorithm in general.

A source can decide which information to store as state and also how to handle failures such as file paths that have been put into state but have been removed from the file system.

It would be great if you could open a JIRA issue with a feature request to improve the failure behavior of the ContinuousFileReaderOperator.

It could for example check if a path exists and before trying to read a file and ignore the input split instead of throwing an exception and causing a failure.

If you want to, you can also work on a fix and contribute it back.

Best, Fabian

2018-02-06 19:15 GMT+01:00 Chengzhi Zhao <[hidden email]>:

Hey, I am new to flink and I have a question and want to see if anyone can help here.

So we have a s3 path that flink is monitoring that path to see new files available.

val avroInputStream_activity = env.readFile(format, path, FileProcessingMode.PROCESS_CONTINUOUSLY, 10000)  

I am doing both internal and external check pointing and let's say there is a bad file came to the path and flink will do several retries. I want to take those bad files and let the process continue. However, since the file path persist in the checkpoint, when I try to resume from external checkpoint, it threw the following error on no file been found.

java.io.IOException: Error opening the Input Split s3a://myfile [0,904]: No such file or directory: s3a://myfile

Is there a way to skip this bad file and move on? 

Thanks in advance.

Best,

Chengzhi Zhao

[Chengzhi Zhao]

Thanks, Fabian, 

I opened an JIRA ticket and I'd like to work on it if people think this would be a improvement:

https://issues.apache.org/jira/browse/FLINK-8599

Best,

Chengzhi

On Wed, Feb 7, 2018 at 4:17 AM, Fabian Hueske <[hidden email]> wrote:

Hi Chengzhi Zhao,

I think this is rather an issue with the ContinuousFileReaderOperator than with the checkpointing algorithm in general.

A source can decide which information to store as state and also how to handle failures such as file paths that have been put into state but have been removed from the file system.

It would be great if you could open a JIRA issue with a feature request to improve the failure behavior of the ContinuousFileReaderOperator.

It could for example check if a path exists and before trying to read a file and ignore the input split instead of throwing an exception and causing a failure.

If you want to, you can also work on a fix and contribute it back.

Best, Fabian

2018-02-06 19:15 GMT+01:00 Chengzhi Zhao <[hidden email]>:

Hey, I am new to flink and I have a question and want to see if anyone can help here.

So we have a s3 path that flink is monitoring that path to see new files available.

val avroInputStream_activity = env.readFile(format, path, FileProcessingMode.PROCESS_CONTINUOUSLY, 10000)  

I am doing both internal and external check pointing and let's say there is a bad file came to the path and flink will do several retries. I want to take those bad files and let the process continue. However, since the file path persist in the checkpoint, when I try to resume from external checkpoint, it threw the following error on no file been found.

java.io.IOException: Error opening the Input Split s3a://myfile [0,904]: No such file or directory: s3a://myfile

Is there a way to skip this bad file and move on? 

Thanks in advance.

Best,

Chengzhi Zhao

[Fabian Hueske-2]

Great, thank you!

Best, Fabian

2018-02-07 23:52 GMT+01:00 Chengzhi Zhao <[hidden email]>:

Thanks, Fabian, 

I opened an JIRA ticket and I'd like to work on it if people think this would be a improvement:

https://issues.apache.org/jira/browse/FLINK-8599

Best,

Chengzhi

On Wed, Feb 7, 2018 at 4:17 AM, Fabian Hueske <[hidden email]> wrote:

Hi Chengzhi Zhao,

I think this is rather an issue with the ContinuousFileReaderOperator than with the checkpointing algorithm in general.

A source can decide which information to store as state and also how to handle failures such as file paths that have been put into state but have been removed from the file system.

It would be great if you could open a JIRA issue with a feature request to improve the failure behavior of the ContinuousFileReaderOperator.

It could for example check if a path exists and before trying to read a file and ignore the input split instead of throwing an exception and causing a failure.

If you want to, you can also work on a fix and contribute it back.

Best, Fabian

2018-02-06 19:15 GMT+01:00 Chengzhi Zhao <[hidden email]>:

Hey, I am new to flink and I have a question and want to see if anyone can help here.

So we have a s3 path that flink is monitoring that path to see new files available.

val avroInputStream_activity = env.readFile(format, path, FileProcessingMode.PROCESS_CONTINUOUSLY, 10000)  

I am doing both internal and external check pointing and let's say there is a bad file came to the path and flink will do several retries. I want to take those bad files and let the process continue. However, since the file path persist in the checkpoint, when I try to resume from external checkpoint, it threw the following error on no file been found.

java.io.IOException: Error opening the Input Split s3a://myfile [0,904]: No such file or directory: s3a://myfile

Is there a way to skip this bad file and move on? 

Thanks in advance.

Best,

Chengzhi Zhao