realdengziqi opened a new pull request #18982:
URL: https://github.com/apache/flink/pull/18982
Co-authored-by: Lin WanNi <linwannid...@foxmail.com>
Co-authored-by: Guo YuanFang <1650213...@qq.com>
## What is the purpose of the change
The goal of this PR is to fix the bug that: the element couldn't be
assigned to the correct window-start, if it's *timestamp - offset + windowSize
< 0*.
This bug located at
_org.apache.flink.streaming.api.windowing.windows.TimeWindow_ .
This problem will be triggered by the negative timestamp, and is caused by
the calculation method of remainder in the JAVA compiler.
Specifically, when we try to calculate the window-start of an incoming
element, if _timestamp - offset + windowSize < 0_, based on the current
calculation formula for window-start, **the element will be right shifted to
the next window, which has a start time larger than the timestamp of current
element**, seems violated the assignment principle for elements on window.
This problem can be fixed by modifying the calculation formula inside the
getWindowStartWithOffset() method as below:
```java
public static long getWindowStartWithOffset(long timestamp, long offset,
long windowSize) {
return timestamp
- (timestamp - offset) % windowSize
- (windowSize & (timestamp - offset) >> 63);
}
```
After this modify, for the element who has negative timestamp, we can still
get the correct window-start. Like the below graph showing:
## Brief change log
- Fix getWindowStartWithOffset in *TimeWindow.java*
## Verifying this change
This change is already covered by existing tests, such as the tests in the
flink-streaming-java [mvn clean verify]
## 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
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Kubernetes/Yarn, 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
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