[
https://issues.apache.org/jira/browse/KAFKA-3160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15234245#comment-15234245
]
Magnus Edenhill commented on KAFKA-3160:
----------------------------------------
[~dana.powers] My broker patch adds a new Attribute bit to specify the fixed
LZ4F framing but still relies on clients being backwards compatible with the
broken framing format, but that was before KIP-31 was a thing..
Your proposed solution with reusing the KIP-31 behaviour is much better, I'd
definately like to see this in broker 0.10.
This will also formally add LZ4 support to the protocol (it is not even
mentioned in the Kafka protocol docs) and be compatible with KIP-35 (e.g.,
ProduceRequest >= v2 supports LZ4).
I'm a strong +1 on this.
> Kafka LZ4 framing code miscalculates header checksum
> ----------------------------------------------------
>
> Key: KAFKA-3160
> URL: https://issues.apache.org/jira/browse/KAFKA-3160
> Project: Kafka
> Issue Type: Bug
> Components: compression
> Affects Versions: 0.8.2.0, 0.8.2.1, 0.9.0.0, 0.8.2.2, 0.9.0.1
> Reporter: Dana Powers
> Assignee: Magnus Edenhill
> Labels: compatibility, compression, lz4
>
> KAFKA-1493 partially implements the LZ4 framing specification, but it
> incorrectly calculates the header checksum. This causes
> KafkaLZ4BlockInputStream to raise an error
> [IOException(DESCRIPTOR_HASH_MISMATCH)] if a client sends *correctly* framed
> LZ4 data. It also causes KafkaLZ4BlockOutputStream to generate incorrectly
> framed LZ4 data, which means clients decoding LZ4 messages from kafka will
> always receive incorrectly framed data.
> Specifically, the current implementation includes the 4-byte MagicNumber in
> the checksum, which is incorrect.
> http://cyan4973.github.io/lz4/lz4_Frame_format.html
> Third-party clients that attempt to use off-the-shelf lz4 framing find that
> brokers reject messages as having a corrupt checksum. So currently non-java
> clients must 'fixup' lz4 packets to deal with the broken checksum.
> Magnus first identified this issue in librdkafka; kafka-python has the same
> problem.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
