GitHub user ggevay opened a pull request:
https://github.com/apache/flink/pull/5041
[FLINK-8117] [runtime] [streaming] Eliminate modulo operation from round
robin partitioners
## What is the purpose of the change
This PR changes `RebalancePartitioner`, `RescalePartitioner`, and
`RoundRobinChannelSelector` to not use `%` for wrapping around when reaching
the number of channels, but use an `if`-statement instead.
## Brief change log
- Make the above change in `RebalancePartitioner`, `RescalePartitioner`,
and `RoundRobinChannelSelector`
- Additionally, I added `final` to the field that is holding the reused
return array in `RebalancePartitioner`, `RoundRobinChannelSelector`,
`ShufflePartitioner`, `ForwardPartitioner`, `GlobalPartitioner`,
`CustomPartitionerWrapper`.
## Verifying this change
This change is already covered by existing tests, such as
`RebalancePartitionerTest`, `RescalePartitionerTest`.
## 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): **yes**
- 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? not applicable
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/ggevay/flink round-robin-no-modulo
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/5041.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 #5041
----
commit 04ff7134e3e5fc750b6f94a385a3ff3bfd921fa3
Author: Gabor Gevay <gga...@gmail.com>
Date: 2017-11-20T14:12:17Z
[FLINK-8117] [runtime] [streaming] Eliminate modulo operation from
round-robin partitioners
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