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From Aljoscha Krettek <aljos...@apache.org>
Subject Re: Behaviour of the BucketingSink when checkpoints fail
Date Fri, 28 Apr 2017 14:11:53 GMT
Hi,
Yes, basically all the exactly-once/at-least-once guarantees are not given if checkpointing
does not work correctly. For example, this will also be the case when reading from Kafka and
writing to Kafka.

Best,
Aljoscha 
> On 28. Apr 2017, at 15:53, Yassine MARZOUGUI <y.marzougui@mindlytix.com> wrote:
> 
> Hi Aljoscha,
> 
> Thank you for your response. I guess then I will manually rename the pending files. Does
this however mean that the BucketingSink is not exactly-once as it is described is the docs,
since in this case (failure of the job and failure of checkpoints) there will be duplicates?
Or am I missing something in the notion of exactly-once guarantees?
> 
> Best,
> Yassine
> 
> 2017-04-28 15:47 GMT+02:00 Aljoscha Krettek <aljoscha@apache.org <mailto:aljoscha@apache.org>>:
> Hi,
> Yes, your analysis is correct. The pending files are not recognised as such because they
were never in any checkpointed state that could be restored. I’m afraid it’s not possible
to build the sink state just from the files existing in the output folder. The reason we have
state in the first place is so that we can figure out what each of the files in the output
folder are.
> 
> Maybe you could manually move the pending files that you know are correct to “final”?
> 
> Best,
> Aljoscha
> 
>> On 28. Apr 2017, at 11:22, Yassine MARZOUGUI <y.marzougui@mindlytix.com <mailto:y.marzougui@mindlytix.com>>
wrote:
>> 
>> Hi all,
>> 
>> I'm have a failed job containing a BucketingSink. The last successful checkpoint
was before the source started emitting data. The following checkpoints all failed due to the
long timeout as I mentioned here : http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Checkpoints-very-slow-with-high-backpressure-td12762.html
<http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Checkpoints-very-slow-with-high-backpressure-td12762.html>.
>> 
>> The Taskmanager has then failed. Upon recovery, the pending fies did not move to
finished state. 
>> 
>> Is that because the sink was not able to checkpoint to list of pending files?
>> Is it possible to build the sink state just from the output folder and the suffixes
of the files?
>> 
>> Thanks,
>> Yassine
> 
> 


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