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https://issues.apache.org/jira/browse/SPARK-5081?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14340089#comment-14340089
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Dr. Christian Betz commented on SPARK-5081:
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Ok, I can really bring the Thread spilling in-memory-map issue down to a
difference from
1.1.0-cdh5.2.0 to 1.1.0. With 1.1.0-cdh5.2.0, everything is fine, with 1.1.0 I
get thread spilling and longer runtimes.
Remember: this is the symptom:
2015-02-27 13:33:41.221 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (9 times so far)
2015-02-27 13:33:41.501 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (10 times so far)
2015-02-27 13:33:41.742 [Executor task launch worker-2 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 77
spilling in-memory map of 27 MB to disk (1 time so far)
2015-02-27 13:33:41.811 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (11 times so far)
2015-02-27 13:33:42.110 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (12 times so far)
2015-02-27 13:33:42.398 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (13 times so far)
2015-02-27 13:33:42.663 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (14 times so far)
2015-02-27 13:33:42.704 [Executor task launch worker-2 ] INFO
org.apache.spark.storage.BlockManager : Found block
rdd_3_33 locally
2015-02-27 13:33:43.045 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (15 times so far)
2015-02-27 13:33:43.367 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (16 times so far)
2015-02-27 13:33:43.637 [Executor task launch worker-6 ] INFO
org.apache.spark.util.collection.ExternalAppendOnlyMap : Thread 109
spilling in-memory map of 0 MB to disk (17 times so far)
> Shuffle write increases
> -----------------------
>
> Key: SPARK-5081
> URL: https://issues.apache.org/jira/browse/SPARK-5081
> Project: Spark
> Issue Type: Bug
> Components: Shuffle
> Affects Versions: 1.2.0
> Reporter: Kevin Jung
> Priority: Critical
> Attachments: Spark_Debug.pdf
>
>
> The size of shuffle write showing in spark web UI is much different when I
> execute same spark job with same input data in both spark 1.1 and spark 1.2.
> At sortBy stage, the size of shuffle write is 98.1MB in spark 1.1 but 146.9MB
> in spark 1.2.
> I set spark.shuffle.manager option to hash because it's default value is
> changed but spark 1.2 still writes shuffle output more than spark 1.1.
> It can increase disk I/O overhead exponentially as the input file gets bigger
> and it causes the jobs take more time to complete.
> In the case of about 100GB input, for example, the size of shuffle write is
> 39.7GB in spark 1.1 but 91.0GB in spark 1.2.
> spark 1.1
> ||Stage Id||Description||Input||Shuffle Read||Shuffle Write||
> |9|saveAsTextFile| |1169.4KB| |
> |12|combineByKey| |1265.4KB|1275.0KB|
> |6|sortByKey| |1276.5KB| |
> |8|mapPartitions| |91.0MB|1383.1KB|
> |4|apply| |89.4MB| |
> |5|sortBy|155.6MB| |98.1MB|
> |3|sortBy|155.6MB| | |
> |1|collect| |2.1MB| |
> |2|mapValues|155.6MB| |2.2MB|
> |0|first|184.4KB| | |
> spark 1.2
> ||Stage Id||Description||Input||Shuffle Read||Shuffle Write||
> |12|saveAsTextFile| |1170.2KB| |
> |11|combineByKey| |1264.5KB|1275.0KB|
> |8|sortByKey| |1273.6KB| |
> |7|mapPartitions| |134.5MB|1383.1KB|
> |5|zipWithIndex| |132.5MB| |
> |4|sortBy|155.6MB| |146.9MB|
> |3|sortBy|155.6MB| | |
> |2|collect| |2.0MB| |
> |1|mapValues|155.6MB| |2.2MB|
> |0|first|184.4KB| | |
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