Fabien created SPARK-38111:
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Summary: Retrieve a Spark dataframe as Arrow batches
Key: SPARK-38111
URL: https://issues.apache.org/jira/browse/SPARK-38111
Project: Spark
Issue Type: Question
Components: Java API
Affects Versions: 3.2.0
Environment: Java 11
Spark 3
Reporter: Fabien
Using the Java API, is there a way to efficiently retrieve a dataframe as Arrow
batches ?
I have a pretty large dataset on my cluster so I cannot collect it using
[collectAsList|https://spark.apache.org/docs/latest/api/java/org/apache/spark/sql/Dataset.html#collectAsList--]
which download every thing at once and saturate the my JVM memory
Seeing that Arrow is becoming a standard to transfer large datasets and that
Spark uses a lot Arrow, is there a way to transfer my Spark dataframe with
Arrow batches ?
This would be ideal to process the data batch per batch and avoid saturating
the memory.
I am looking for an API like this (in Java)
{code:java}
var stream = dataframe.collectAsArrowStream()
while (stream.hasNextBatch()) {
var batch = stream.getNextBatch()
// do some stuff with the arrow batch
}
{code}
It would be even better if I can split the dataframe into several streams so I
can download and process it in parallel
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