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https://issues.apache.org/jira/browse/SPARK-46639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Eren Avsarogullari updated SPARK-46639:
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Attachment: WindowExec SQLMetrics.png
> Add WindowExec SQLMetrics
> -------------------------
>
> Key: SPARK-46639
> URL: https://issues.apache.org/jira/browse/SPARK-46639
> Project: Spark
> Issue Type: Task
> Components: SQL
> Affects Versions: 4.0.0
> Reporter: Eren Avsarogullari
> Priority: Major
> Labels: pull-request-available
> Attachments: WindowExec SQLMetrics.png
>
>
> Currently, WindowExec Physical Operator has only spillSize SQLMetric. This
> jira aims to add following SQLMetrics to provide more information from
> WindowExec usage during query execution:
> {code:java}
> numOfOutputRows: Number of total output rows.
> numOfPartitions: Number of processed input partitions.
> numOfWindowPartitions: Number of generated window partitions.
> spilledRows: Number of total spilled rows.
> spillSizeOnDisk: Total spilled data size on disk.{code}
> As an example use-case, WindowExec spilling behavior depends on multiple
> factors and it can sometime cause {{SparkOutOfMemoryError}} instead of
> spilling to disk so it is hard to track without SQL Metrics such as:
> *1-* WindowExec creates ExternalAppendOnlyUnsafeRowArray (internal
> ArrayBuffer) per task (a.k.a child RDD partition)
> *2-* When ExternalAppendOnlyUnsafeRowArray size exceeds
> spark.sql.windowExec.buffer.in.memory.threshold=4096,
> ExternalAppendOnlyUnsafeRowArray switches to UnsafeExternalSorter as
> spillableArray by moving its all buffered rows into UnsafeExternalSorter and
> ExternalAppendOnlyUnsafeRowArray (internal ArrayBuffer) is cleared. In this
> case, WindowExec starts to write UnsafeExternalSorter' s buffer (a.k.a
> UnsafeInMemorySorter).
> *3-* UnsafeExternalSorter is being created per window partition. When
> UnsafeExternalSorter' buffer size exceeds
> spark.sql.windowExec.buffer.spill.threshold=Integer.MAX_VALUE, it starts to
> write to disk and get cleared all buffer (a.k.a UnsafeInMemorySorter)
> content. In this case, UnsafeExternalSorter will continue to buffer next
> records until exceeding spark.sql.windowExec.buffer.spill.threshold.
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