Timm0 opened a new pull request, #29051:
URL: https://github.com/apache/flink/pull/29051
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## Contribution Checklist
- Make sure that the pull request corresponds to a [JIRA
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## What is the purpose of the change
The batch planner compiles `ROW_NUMBER() OVER (PARTITION BY … ORDER BY …) …
WHERE rn <= N` to a single-stage `OverAggregate` that hash-shuffles and sorts
the entire input before dropping all but the top rows. This change routes that
pattern through the existing two-stage `Rank` (a local top-N before the
shuffle, and a global top-N after), so only the local survivors cross the
`Exchange`. It is a rule-based conversion at the logical phase, aligning batch
with streaming.
## Brief change log
- Relax the `RANK`-only guards in `FlinkLogicalRankRuleForConstantRange` and
`BatchPhysicalRankRule` to also admit `ROW_NUMBER`, routing batch `ROW_NUMBER()
… WHERE rn <= N` (constant range) to the two-stage `Rank` instead of
`OverAggregate`
- Add a `RankType` parameter to `RankOperator`, emit on the row-number
counter for `ROW_NUMBER`, and on the rank counter for `RANK`
- Add `RankOperatorTest` and `RowNumberITCase` regenerate the flipped
`ROW_NUMBER` goldens in `RankTest.xml` and
`FlinkLogicalRankRuleForConstantRangeTest.xml`
- Add the `ROW_NUMBER_TOP_N` compiled-plan restore program + JSON
## Verifying this change
- Added `RankOperatorTest` and `RowNumberITCase` regenerate the flipped
`ROW_NUMBER` goldens in `RankTest.xml` and
`FlinkLogicalRankRuleForConstantRangeTest.xml`
- Added the `ROW_NUMBER_TOP_N` compiled-plan restore program + JSON
I also ran some benchmark tests on a dataset with near-unique keys (1 row
per key) and lot's of duplicated keys (~1800 rows per key). Below are the
results:
1. ` ROW_NUMBER() OVER (PARTITION BY ... ORDER BY ... DESC) AS rn ... WHERE
rn = 1`
**Near-unique Keys**:
- performance decrease of ~12%
- exchanged rows decreased by ~10%
**Duplicated Keys**:
- performance increase of ~48%
- exchanged rows decreased by ~10%
2. ` ROW_NUMBER() OVER (PARTITION BY ... ORDER BY ... DESC) AS rn ... WHERE
rn <= 200`
**Near-unique Keys**:
- performance increase of ~7%
- exchanged rows decreased by ~1%
**Duplicated Keys**:
- performance decrease of ~2%
- exchanged rows decreased by ~1%
## 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, 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? na
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