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From Yichen Zhou <zhouy...@gmail.com>
Subject Re: Shuffle write explosion
Date Tue, 06 Nov 2018 14:18:51 GMT
Hi Dillon,

Thank you for your reply.
mapToPair use a PairFunction to transform format to a particular parquet
format. I have tried to replace the mapToPair() function with other action
operators like count() or collect(), but it didn't work. So I guess the
shuffle write explosion problem have no concern with mapToPair().

Best Regrads,
Yichen

Dillon Dukek <dillon.dukek@placed.com> 于2018年11月6日周二 上午7:21写道:

> What is your function in mapToPair doing?
>
> -Dillon
>
> On Mon, Nov 5, 2018 at 1:41 PM Taylor Cox <Taylor.Cox@microsoft.com.invalid>
> wrote:
>
>> At first glance, I wonder if your tables are partitioned? There may not
>> be enough parallelism happening. You can also pass in the number of
>> partitions and/or a custom partitioner to help Spark “guess” how to
>> organize the shuffle.
>>
>>
>>
>> Have you seen any of these docs?
>>
>>
>> https://people.eecs.berkeley.edu/~kubitron/courses/cs262a-F13/projects/reports/project16_report.pdf
>>
>> https://spark.apache.org/docs/latest/tuning.html
>>
>>
>>
>> Taylor
>>
>>
>>
>>
>>
>> *From:* Yichen Zhou <zhouycsf@gmail.com>
>> *Sent:* Sunday, November 4, 2018 11:42 PM
>> *To:* user@spark.apache.org
>> *Subject:* Shuffle write explosion
>>
>>
>>
>> Hi All,
>>
>>
>>
>> When running a spark job, I have 100MB+ input and get more than 700GB
>> shuffle write, which is really weird. And this job finally end up with the
>> OOM error. Does anybody know why this happened?
>>
>> [image: Screen Shot 2018-11-05 at 15.20.35.png]
>>
>> My code is like:
>>
>> JavaPairRDD<Text, Text> inputRDD = sc.sequenceFile(inputPath, Text.class,
>> Text.class);
>>
>>
>>  inputRDD.repartition(partitionNum).mapToPair(...).saveAsNewAPIHadoopDataset(job.getConfiguration())
>> ;
>>
>>
>> Environment:
>>
>> *CPU 32 core; Memory 256G; Storage 7.5G CentOS 7.5*
>>
>> *java version "1.8.0_162"*
>>
>> *Spark 2.1.2*
>>
>>
>> Any help is greatly appreciated.
>>
>>
>>
>> Regards,
>>
>> Yichen
>>
>

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