Hi Aljoscha,
oh I see. I was under the impression this file was used internally and the
output being completed at the end. Ok, so I extracted the relevant lines using
for i in part-*; do head -c $(cat "_$i.valid-length" | strings) "$i" >
"$i.final"; done
which seems to do the trick.
Unfortunately, now some records are missing again. In particular, there are the
files
part-0-0, part-1-0, ..., part-10-0, part-11-0, each with corresponding
.valid-length files
part-0-1, part-1-1, ..., part-10-0
in the bucket, where job parallelism=12. So it looks to us as if one of the
files was not even created in the second attempt. This behavior seems to be
what somewhat reproducible, cf. my earlier email where the part-11 file
disappeared as well.
Thanks again for your help.
Cheers,
Max
—
Maximilian Bode * Junior Consultant * maximilian.b...@tngtech.com
TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterföhring
Geschäftsführer: Henrik Klagges, Christoph Stock, Dr. Robert Dahlke
Sitz: Unterföhring * Amtsgericht München * HRB 135082
> Am 08.03.2016 um 11:05 schrieb Aljoscha Krettek <aljos...@apache.org>:
>
> Hi,
> are you taking the “.valid-length” files into account. The problem with doing
> “exactly-once” with HDFS is that before Hadoop 2.7 it was not possible to
> truncate files. So the trick we’re using is to write the length up to which a
> file is valid if we would normally need to truncate it. (If the job fails in
> the middle of writing the output files have to be truncated to a valid
> position.) For example, say you have an output file part-8-0. Now, if there
> exists a file part-8-0.valid-length this file tells you up to which position
> the file part-8-0 is valid. So you should only read up to this point.
>
> The name of the “.valid-length” suffix can also be configured, by the way, as
> can all the other stuff.
>
> If this is not the problem then I definitely have to investigate further.
> I’ll also look into the Hadoop 2.4.1 build problem.
>
> Cheers,
> Aljoscha
>> On 08 Mar 2016, at 10:26, Maximilian Bode <maximilian.b...@tngtech.com>
>> wrote:
>>
>> Hi Aljoscha,
>> thanks again for getting back to me. I built from your branch and the
>> exception is not occurring anymore. The RollingSink state can be restored.
>>
>> Still, the exactly-once guarantee seems not to be fulfilled, there are
>> always some extra records after killing either a task manager or the job
>> manager. Do you have an idea where this behavior might be coming from? (I
>> guess concrete numbers will not help greatly as there are so many parameters
>> influencing them. Still, in our test scenario, we produce 2 million records
>> in a Kafka queue but in the final output files there are on the order of 2.1
>> million records, so a 5% error. The job is running in a per-job YARN session
>> with n=3, s=4 with a checkpointing interval of 10s.)
>>
>> On another (maybe unrelated) note: when I pulled your branch, the Travis
>> build did not go through for -Dhadoop.version=2.4.1. I have not looked into
>> this further as of now, is this one of the tests known to fail sometimes?
>>
>> Cheers,
>> Max
>> <travis.log>
>> —
>> Maximilian Bode * Junior Consultant * maximilian.b...@tngtech.com
>> TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterföhring
>> Geschäftsführer: Henrik Klagges, Christoph Stock, Dr. Robert Dahlke
>> Sitz: Unterföhring * Amtsgericht München * HRB 135082
>>
>>> Am 07.03.2016 um 17:20 schrieb Aljoscha Krettek <aljos...@apache.org>:
>>>
>>> Hi Maximilian,
>>> sorry for the delay, we where very busy with the release last week. I had a
>>> hunch about the problem but I think I found a fix now. The problem is in
>>> snapshot restore. When restoring, the sink tries to clean up any files that
>>> where previously in progress. If Flink restores to the same snapshot twice
>>> in a row then it will try to clean up the leftover files twice but they are
>>> not there anymore, this causes the exception.
>>>
>>> I have a fix in my branch:
>>> https://github.com/aljoscha/flink/tree/rolling-sink-fix
>>>
>>> Could you maybe try if this solves your problem? Which version of Flink are
>>> you using? You would have to build from source to try it out. Alternatively
>>> I could build it and put it onto a maven snapshot repository for you to try
>>> it out.
>>>
>>> Cheers,
>>> Aljoscha
>>>> On 03 Mar 2016, at 14:50, Aljoscha Krettek <aljos...@apache.org> wrote:
>>>>
>>>> Hi,
>>>> did you check whether there are any files at your specified HDFS output
>>>> location? If yes, which files are there?
>>>>
>>>> Cheers,
>>>> Aljoscha
>>>>> On 03 Mar 2016, at 14:29, Maximilian Bode <maximilian.b...@tngtech.com>
>>>>> wrote:
>>>>>
>>>>> Just for the sake of completeness: this also happens when killing a task
>>>>> manager and is therefore probably unrelated to job manager HA.
>>>>>
>>>>>> Am 03.03.2016 um 14:17 schrieb Maximilian Bode
>>>>>> <maximilian.b...@tngtech.com>:
>>>>>>
>>>>>> Hi everyone,
>>>>>>
>>>>>> unfortunately, I am running into another problem trying to establish
>>>>>> exactly once guarantees (Kafka -> Flink 1.0.0-rc3 -> HDFS).
>>>>>>
>>>>>> When using
>>>>>>
>>>>>> RollingSink<Tuple3<Integer,Integer,String>> sink = new
>>>>>> RollingSink<Tuple3<Integer,Integer,String>>("hdfs://our.machine.com:8020/hdfs/dir/outbound");
>>>>>> sink.setBucketer(new NonRollingBucketer());
>>>>>> output.addSink(sink);
>>>>>>
>>>>>> and then killing the job manager, the new job manager is unable to
>>>>>> restore the old state throwing
>>>>>> ---
>>>>>> java.lang.Exception: Could not restore checkpointed state to operators
>>>>>> and functions
>>>>>> at
>>>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.restoreState(StreamTask.java:454)
>>>>>> at
>>>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:209)
>>>>>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
>>>>>> at java.lang.Thread.run(Thread.java:744)
>>>>>> Caused by: java.lang.Exception: Failed to restore state to function:
>>>>>> In-Progress file hdfs://our.machine.com:8020/hdfs/dir/outbound/part-5-0
>>>>>> was neither moved to pending nor is still in progress.
>>>>>> at
>>>>>> org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.restoreState(AbstractUdfStreamOperator.java:168)
>>>>>> at
>>>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.restoreState(StreamTask.java:446)
>>>>>> ... 3 more
>>>>>> Caused by: java.lang.RuntimeException: In-Progress file
>>>>>> hdfs://our.machine.com:8020/hdfs/dir/outbound/part-5-0 was neither moved
>>>>>> to pending nor is still in progress.
>>>>>> at
>>>>>> org.apache.flink.streaming.connectors.fs.RollingSink.restoreState(RollingSink.java:686)
>>>>>> at
>>>>>> org.apache.flink.streaming.connectors.fs.RollingSink.restoreState(RollingSink.java:122)
>>>>>> at
>>>>>> org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.restoreState(AbstractUdfStreamOperator.java:165)
>>>>>> ... 4 more
>>>>>> ---
>>>>>> I found a resolved issue [1] concerning Hadoop 2.7.1. We are in fact
>>>>>> using 2.4.0 – might this be the same issue?
>>>>>>
>>>>>> Another thing I could think of is that the job is not configured
>>>>>> correctly and there is some sort of timing issue. The checkpoint
>>>>>> interval is 10 seconds, everything else was left at default value. Then
>>>>>> again, as the NonRollingBucketer is used, there should not be any timing
>>>>>> issues, right?
>>>>>>
>>>>>> Cheers,
>>>>>> Max
>>>>>>
>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-2979
>>>>>>
>>>>>> —
>>>>>> Maximilian Bode * Junior Consultant * maximilian.b...@tngtech.com
>>>>>> TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterföhring
>>>>>> Geschäftsführer: Henrik Klagges, Christoph Stock, Dr. Robert Dahlke
>>>>>> Sitz: Unterföhring * Amtsgericht München * HRB 135082
>>>>>>
>>>>>
>>>>
>>>
>>
>
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