wangyum opened a new pull request #33105:
URL: https://github.com/apache/spark/pull/33105
### What changes were proposed in this pull request?
Enhance `OptimizeRepartition` to remove repartition if the child maximum
number of rows less than or equal to 1. For example:
```scala
spark.sql("select count(*) from range(1, 10, 2,
2)").repartition(10).explain("cost")
```
Before this PR:
```
== Optimized Logical Plan ==
Repartition 10, true, Statistics(sizeInBytes=16.0 B, rowCount=1)
+- Aggregate [count(1) AS count(1)#2L], Statistics(sizeInBytes=16.0 B,
rowCount=1)
+- Project, Statistics(sizeInBytes=20.0 B)
+- Range (1, 10, step=2, splits=Some(2)), Statistics(sizeInBytes=40.0
B, rowCount=5)
```
After this PR:
```
== Optimized Logical Plan ==
Aggregate [count(1) AS count(1)#2L], Statistics(sizeInBytes=16.0 B,
rowCount=1)
+- Project, Statistics(sizeInBytes=20.0 B)
+- Range (1, 10, step=2, splits=Some(2)), Statistics(sizeInBytes=40.0 B,
rowCount=5)
```
### Why are the changes needed?
Improve query performance.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Unit test.
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