sarutak opened a new pull request #29681:
URL: https://github.com/apache/spark/pull/29681
### What changes were proposed in this pull request?
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This PR changes the behavior of RangeExec with WholeStageCodegen disabled or
falled back to change the number of partitions to zero when a range is empty.
In the current master, if WholeStageCodegen effects, the number of
partitions of an empty range will be changed to zero.
```
spark.range(1, 1, 1, 1000).rdd.getNumPartitions
res0: Int = 0
```
But it doesn't if WholeStageCodegen is disabled or falled back.
```
spark.conf.set("spark.sql.codegen.wholeStage", false)
spark.range(1, 1, 1, 1000).rdd.getNumPartitions
res2: Int = 1000
```
### Why are the changes needed?
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To archive better performance even though WholeStageCodegen disabled or
falled back.
### Does this PR introduce _any_ user-facing change?
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the documentation fix.
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the released Spark versions or within the unreleased branches such as master.
If no, write 'No'.
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Yes. the number of partitions gotten with `getNumPartitions` for an empty
range will be changed when WholeStageCodegen is disabled.
### How was this patch tested?
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New test.
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