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https://issues.apache.org/jira/browse/SPARK-3000?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Owen updated SPARK-3000:
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Target Version/s: (was: 1.3.0)
> drop old blocks to disk in parallel when memory is not large enough for
> caching new blocks
> ------------------------------------------------------------------------------------------
>
> Key: SPARK-3000
> URL: https://issues.apache.org/jira/browse/SPARK-3000
> Project: Spark
> Issue Type: Improvement
> Components: Spark Core
> Affects Versions: 1.1.0
> Reporter: Zhang, Liye
> Assignee: Zhang, Liye
> Attachments: Spark-3000 Design Doc.pdf
>
>
> In spark, rdd can be cached in memory for later use, and the cached memory
> size is "*spark.executor.memory * spark.storage.memoryFraction*" for spark
> version before 1.1.0, and "*spark.executor.memory *
> spark.storage.memoryFraction * spark.storage.safetyFraction*" after
> [SPARK-1777|https://issues.apache.org/jira/browse/SPARK-1777].
> For Storage level *MEMORY_AND_DISK*, when free memory is not enough to cache
> new blocks, old blocks might be dropped to disk to free up memory for new
> blocks. This operation is processed by _ensureFreeSpace_ in
> _MemoryStore.scala_, there will always be a "*accountingLock*" held by the
> caller to ensure only one thread is dropping blocks. This method can not
> fully used the disks throughput when there are multiple disks on the working
> node. When testing our workload, we found this is really a bottleneck when
> size of old blocks to be dropped is really large.
> We have tested the parallel method on spark 1.0, the speedup is significant.
> So it's necessary to make dropping blocks operation in parallel.
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