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https://issues.apache.org/jira/browse/SPARK-21033?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wenchen Fan resolved SPARK-21033.
---------------------------------
Resolution: Fixed
Fix Version/s: 2.3.0
> fix the potential OOM in UnsafeExternalSorter
> ---------------------------------------------
>
> Key: SPARK-21033
> URL: https://issues.apache.org/jira/browse/SPARK-21033
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.2.0
> Reporter: Wenchen Fan
> Assignee: Wenchen Fan
> Fix For: 2.3.0
>
>
> In `UnsafeInMemorySorter`, one record may take 32 bytes: 1 `long` for
> pointer, 1 `long` for key-prefix, and another 2 `long`s as the temporary
> buffer for radix sort.
> In `UnsafeExternalSorter`, we set the
> `DEFAULT_NUM_ELEMENTS_FOR_SPILL_THRESHOLD` to be `1024 * 1024 * 1024 / 2`,
> and hoping the max size of point array to be 8 GB. However this is wrong,
> `1024 * 1024 * 1024 / 2 * 32` is actually 16 GB, and if we grow the point
> array before reach this limitation, we may hit the max-page-size error.
> Users may see exception like this on large dataset:
> {code}
> Caused by: java.lang.IllegalArgumentException: Cannot allocate a page with
> more than 17179869176 bytes
> at
> org.apache.spark.memory.TaskMemoryManager.allocatePage(TaskMemoryManager.java:241)
> at
> org.apache.spark.memory.MemoryConsumer.allocatePage(MemoryConsumer.java:121)
> at
> org.apache.spark.util.collection.unsafe.sort.UnsafeExternalSorter.acquireNewPageIfNecessary(UnsafeExternalSorter.java:374)
> at
> org.apache.spark.util.collection.unsafe.sort.UnsafeExternalSorter.insertRecord(UnsafeExternalSorter.java:396)
> at
> org.apache.spark.sql.execution.UnsafeExternalRowSorter.insertRow(UnsafeExternalRowSorter.java:94)
> ...
> {code}
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