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https://issues.apache.org/jira/browse/KAFKA-3704?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gwen Shapira resolved KAFKA-3704.
---------------------------------
Resolution: Fixed
Fix Version/s: 0.10.0.0
Issue resolved by pull request 1391
[https://github.com/apache/kafka/pull/1391]
> Improve mechanism for compression stream block size selection in KafkaProducer
> ------------------------------------------------------------------------------
>
> Key: KAFKA-3704
> URL: https://issues.apache.org/jira/browse/KAFKA-3704
> Project: Kafka
> Issue Type: Bug
> Reporter: Guozhang Wang
> Assignee: Ismael Juma
> Fix For: 0.10.1.0, 0.10.0.0
>
>
> As discovered in https://issues.apache.org/jira/browse/KAFKA-3565, the
> current default block size (1K) used in Snappy and GZIP may cause a
> sub-optimal compression ratio for Snappy, and hence reduce throughput.
> Because we no longer recompress data in the broker, it also impacts what gets
> stored on disk.
> A solution might be to use the default block size, which is 64K in LZ4, 32K
> in Snappy and 0.5K in GZIP. The downside is that this solution will require
> more memory allocated outside of the buffer pool and hence users may need to
> bump up their JVM heap size, especially for MirrorMakers. Using Snappy as an
> example, it's an additional 2x32k per batch (as Snappy uses two buffers) and
> one would expect at least one batch per partition. However, the number of
> batches per partition can be much higher if the broker is slow to acknowledge
> producer requests (depending on `buffer.memory`, `batch.size`, message size,
> etc.).
> Given the above, it seems like a configuration may be needed as the there is
> no one size fits all. An alternative to a new config is to allocate buffers
> from the buffer pool and pass them to the compression library. This is
> possible with Snappy and we could adapt our LZ4 code. It's not possible with
> GZIP, but it uses a very small buffer by default.
> Note that we decided that this change was too risky for 0.10.0.0 and reverted
> the original attempt.
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