GitHub user NicoK opened a pull request:
https://github.com/apache/flink/pull/5570
[FLINK-8768][network] Let NettyMessageDecoder inherit from
LengthFieldBasedFrameDecoder
## What is the purpose of the change
Instead of being two steps in the channel pipeline, `NettyMessageDecoder`
could derive from `LengthFieldBasedFrameDecoder` to reduce overhead and give us
more control over the protocol.
As a first step, we will use this to override the `#extractFrame()` method
to restore the old Netty 4.0.27 behaviour for non-credit based code paths which
had a bug with Netty >= 4.0.28 (see FLINK-8759).
## Brief change log
- make `NettyMessageDecoder` inherit from `LengthFieldBasedFrameDecoder`
(beware that this changes the decoder from a `MessageToMessageDecoder` to a
`ByteToMessageDecoder` with different cleanup invariants!)
## Verifying this change
This change is already covered by existing tests, such as
`NettyMessageSerializationTest` or other network tests using the
encoding/decoding pipeline.
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): **no**
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: **no**
- The serializers: **no**
- The runtime per-record code paths (performance sensitive): **no** (only
per buffer)
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Yarn/Mesos, ZooKeeper: **no**
- The S3 file system connector: **no**
## Documentation
- Does this pull request introduce a new feature? **no**
- If yes, how is the feature documented? (JavaDocs)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/NicoK/flink flink-8768
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/5570.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #5570
----
commit 272899e01c2836a2a5b47958db7d9d9f6cbf471d
Author: Nico Kruber <nico@...>
Date: 2018-02-23T12:56:29Z
[FLINK-8768][network] Let NettyMessageDecoder inherit from
LengthFieldBasedFrameDecoder
This replaces one additional step from the pipeline and does not only remove
overhead there but also allows use to override the #extractFrame() method to
restore the old Netty 4.0.27 behaviour for non-credit based code paths which
had a bug with Netty >= 4.0.28 there (see FLINK-8759).
----
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