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author | gatorsmile <gatorsmile@gmail.com> | 2016-03-21 10:34:54 +0800 |
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committer | Wenchen Fan <wenchen@databricks.com> | 2016-03-21 10:34:54 +0800 |
commit | f58319a24fd5e026411538b1fb7336d9d894277b (patch) | |
tree | c109f1f3e23cacf6f0cb4f0d2c78088f5514f531 /python/docs/Makefile | |
parent | 454a00df2a43176cb774cad7277934a775618db1 (diff) | |
download | spark-f58319a24fd5e026411538b1fb7336d9d894277b.tar.gz spark-f58319a24fd5e026411538b1fb7336d9d894277b.tar.bz2 spark-f58319a24fd5e026411538b1fb7336d9d894277b.zip |
[SPARK-14019][SQL] Remove noop SortOrder in Sort
#### What changes were proposed in this pull request?
This PR is to add a new Optimizer rule for pruning Sort if its SortOrder is no-op. In the phase of **Optimizer**, if a specific `SortOrder` does not have any reference, it has no effect on the sorting results. If `Sort` is empty, remove the whole `Sort`.
For example, in the following SQL query
```SQL
SELECT * FROM t ORDER BY NULL + 5
```
Before the fix, the plan is like
```
== Analyzed Logical Plan ==
a: int, b: int
Sort [(cast(null as int) + 5) ASC], true
+- Project [a#92,b#93]
+- SubqueryAlias t
+- Project [_1#89 AS a#92,_2#90 AS b#93]
+- LocalRelation [_1#89,_2#90], [[1,2],[1,2]]
== Optimized Logical Plan ==
Sort [null ASC], true
+- LocalRelation [a#92,b#93], [[1,2],[1,2]]
== Physical Plan ==
WholeStageCodegen
: +- Sort [null ASC], true, 0
: +- INPUT
+- Exchange rangepartitioning(null ASC, 5), None
+- LocalTableScan [a#92,b#93], [[1,2],[1,2]]
```
After the fix, the plan is like
```
== Analyzed Logical Plan ==
a: int, b: int
Sort [(cast(null as int) + 5) ASC], true
+- Project [a#92,b#93]
+- SubqueryAlias t
+- Project [_1#89 AS a#92,_2#90 AS b#93]
+- LocalRelation [_1#89,_2#90], [[1,2],[1,2]]
== Optimized Logical Plan ==
LocalRelation [a#92,b#93], [[1,2],[1,2]]
== Physical Plan ==
LocalTableScan [a#92,b#93], [[1,2],[1,2]]
```
cc rxin cloud-fan marmbrus Thanks!
#### How was this patch tested?
Added a test suite for covering this rule
Author: gatorsmile <gatorsmile@gmail.com>
Closes #11840 from gatorsmile/sortElimination.
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