zhangdenghui created SPARK-19007:
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Summary: Speedup and optimize the GradientBoostedTrees in the
"data>memory" scene
Key: SPARK-19007
URL: https://issues.apache.org/jira/browse/SPARK-19007
Project: Spark
Issue Type: Improvement
Components: ML, MLlib
Affects Versions: 2.1.0, 2.0.2, 2.0.1, 2.0.0, 1.6.3, 1.6.2, 1.6.1, 1.6.0,
1.5.2, 1.5.1, 1.5.0
Environment: A CDH cluster consists of 3 redhat server ,(120G
memory、40 cores、43TB disk per server).
Reporter: zhangdenghui
Fix For: 2.1.0
Test data：80G CTR training data from
criteolabs(http://criteolabs.wpengine.com/downloads/download-terabyte-click-logs/),I
used 1 of the 24 days' data.Some features needed to be repalced by new
generated continuous features，the way to generate the new features refers to
the way mentioned in the xgboost's paper.
Recource allocated: spark on yarn, 20 executors, 8G memory and 2 cores per
executor.
I tested the GradientBoostedTrees algorithm in mllib using 80G CTR data
mentioned above.
It totally costs 1.5 hour, and i found many task failures after 6 or 7 GBT
rounds later.Without these task failures and task retry it can be much faster
,which can save about half the time. I think it's caused by the RDD named
predError in the while loop of the boost method at
GradientBoostedTrees.scala,because the lineage of the RDD named predError is
growing after every GBT round, and then it caused failures like this :
(ExecutorLostFailure (executor 6 exited caused by one of the running tasks)
Reason: Container killed by YARN for exceeding memory limits. 10.2 GB of 10 GB
physical memory used. Consider boosting spark.yarn.executor.memoryOverhead.).
I tried to boosting spark.yarn.executor.memoryOverhead but the meomry it
needed is too much (even increase half the memory can't solve the problem) so
i think it's not a proper method.
Although it can set the predCheckpoint Interval smaller to cut the line of
the lineage but it increases IO cost a lot.
I tried another way to solve this problem.I persisted the RDD named predError
every round and use pre_predError to record the previous RDD and unpersist
it because it's useless anymore.
Finally it costs about 45 min after i tried my method and no task failure
occured and no more memeory added.
So when the data is much larger than memory, my little improvement can speedup
the GradientBoostedTrees 1~2 times.
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