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https://issues.apache.org/jira/browse/SPARK-18252?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15674532#comment-15674532
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Reynold Xin commented on SPARK-18252:
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I'm not sure if it is worth fixing this:
1. We already compress data before we send them across the network.
2. This is also not a backward compatible change would require different
versioning.
3. This brings in extra dependency for a package that has 0 external dependency.
4. We very likely will implement vectorized probing for bloom filter to be used
in Spark SQL joins, and using roaring bitmap would make that a lot harder to do.
> Improve serialized BloomFilter size
> -----------------------------------
>
> Key: SPARK-18252
> URL: https://issues.apache.org/jira/browse/SPARK-18252
> Project: Spark
> Issue Type: Improvement
> Components: Spark Core
> Affects Versions: 2.0.1
> Reporter: Aleksey Ponkin
> Priority: Minor
>
> Since version 2.0 Spark has BloomFilter implementation -
> org.apache.spark.util.sketch.BloomFilterImpl. I have noticed that current
> implementation is using custom class org.apache.spark.util.sketch.BitArray
> for bit vector, which is allocating memory for the whole filter no matter how
> many elements are set. Since BloomFilter can be serialized and sent over
> network in distribution stage may be we need to use some kind of compressed
> bloom filters? For example
> [https://github.com/RoaringBitmap/RoaringBitmap][RoaringBitmap] or
> [javaewah][https://github.com/lemire/javaewah].
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