spark-instrumented-optimizer/sql/catalyst
Yuming Wang 4a17e7a5ae [SPARK-35906][SQL] Remove order by if the maximum number of rows less than or equal to 1
### What changes were proposed in this pull request?

This PR removes order by if the maximum number of rows less than or equal to 1. For example:
```scala
spark.sql("select count(*) from range(1, 10, 2, 2) order by 1 limit 10").explain("cost")
```
Before this pr:
```
== Optimized Logical Plan ==
Sort [count(1)#2L ASC NULLS FIRST], true, Statistics(sizeInBytes=16.0 B)
+- 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.

Closes #33100 from wangyum/SPARK-35906.

Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
2021-06-29 11:04:54 -07:00
..
benchmarks [SPARK-34950][TESTS] Update benchmark results to the ones created by GitHub Actions machines 2021-04-03 23:02:56 +03:00
src [SPARK-35906][SQL] Remove order by if the maximum number of rows less than or equal to 1 2021-06-29 11:04:54 -07:00
pom.xml [SPARK-33212][BUILD] Upgrade to Hadoop 3.2.2 and move to shaded clients for Hadoop 3.x profile 2021-01-15 14:06:50 -08:00