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https://issues.apache.org/jira/browse/SPARK-60395?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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L. C. Hsieh updated SPARK-60395:
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Affects Version/s: 4.2.0
4.1.3
4.3.0
4.4.0
(was: 5.0.0)
> Fix the batch size computation and limit check of maxBytesPerOutputBatch in
> sliced Arrow output
> -----------------------------------------------------------------------------------------------
>
> Key: SPARK-60395
> URL: https://issues.apache.org/jira/browse/SPARK-60395
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 4.2.0, 4.3.0, 4.1.3, 4.4.0
> Reporter: L. C. Hsieh
> Priority: Major
>
> SliceBytesArrowOutputProcessorImpl, used when the internal config
> spark.sql.execution.arrow.maxBytesPerOutputBatch is set, has two problems in
> how it measures and compares the size of an output batch:
> 1. getBatchBytes sums FieldVector.getBufferSize of the top-level vectors into
> a Long, but for a struct vector the size is already truncated to an int
> inside Arrow: NonNullableStructVector.getBufferSize sums its children in a
> long and returns (int) buffer, and StructVector adds its validity size as an
> int. The outputs of mapInArrow, mapInPandas, applyInPandas and Python UDTFs
> are wrapped in one top-level struct vector, so a batch over 2 GiB can be
> measured as a negative size. For example, a mapInArrow UDF that yields one
> batch of three int64 columns with 2^27 rows (about 3 GiB) is measured as
> -1,006,632,960 bytes, so with maxBytesPerOutputBatch=256m the whole batch is
> output without slicing. The check on each slice can accept an oversized slice
> the same way. The size should be computed by summing the buffer sizes of the
> leaf vectors (and the validity buffers of the nested vectors) as Long.
> 2. The doc of spark.sql.execution.arrow.maxBytesPerOutputBatch says Spark
> will try to create batches with the size equal or less than the value, but
> both checks in SliceBytesArrowOutputProcessorImpl use <, so a batch whose
> size equals the limit exactly is sliced. The records processor uses <=. The
> checks or the doc should be aligned.
> Found while reviewing SPARK-60367
> (https://github.com/apache/spark/pull/59616), which this builds on.
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