GitHub user dongjoon-hyun opened a pull request:
https://github.com/apache/spark/pull/12850
[SPARK-15076][SQL] Improve ConstantFolding optimizer by using integral
associative property
## What changes were proposed in this pull request?
This issue improves `ConstantFolding` optimizer by taking advantage of
integral associative property. Currently, `ConstantFolding` works like the
following.
1) Can optimize `1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + a` into `45 + a`.
2) Cannot optimize `a + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9`.
This issue enables `ConstantFolding` to handle Case 2 for Add/Multiply
expression whose data types are `ByteType`, `ShortType`, `IntegerType`, and
`LongType`. The followings are the plan comparision between `before` and
`after` this issue.
**Before**
```
scala> sql("select a+1+2+3+4+5+6+7+8+9 from (select explode(array(1))
a)").explain
== Physical Plan ==
WholeStageCodegen
: +- Project [(((((((((a#7 + 1) + 2) + 3) + 4) + 5) + 6) + 7) + 8) + 9) AS
(((((((((a + 1) + 2) + 3) + 4) + 5) + 6) + 7) + 8) + 9)#8]
: +- INPUT
+- Generate explode([1]), false, false, [a#7]
+- Scan OneRowRelation[]
```
**After**
```
scala> sql("select a+1+2+3+4+5+6+7+8+9 from (select explode(array(1))
a)").explain
== Physical Plan ==
WholeStageCodegen
: +- Project [(a#7 + 45) AS (((((((((a + 1) + 2) + 3) + 4) + 5) + 6) + 7)
+ 8) + 9)#8]
: +- INPUT
+- Generate explode([1]), false, false, [a#7]
+- Scan OneRowRelation[]
```
## How was this patch tested?
Pass the Jenkins tests including new and updated testcases.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/dongjoon-hyun/spark SPARK-15076
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/12850.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #12850
----
commit 71c3c73ad0f507837539ed58489e63e501bd4c3d
Author: Dongjoon Hyun <dongj...@apache.org>
Date: 2016-05-02T22:38:31Z
[SPARK-15076][SQL] Improve ConstantFolding optimizer by using integral
associative property.
----
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
