Skip to content
Snippets Groups Projects
Commit 99bd2f0e authored by gatorsmile's avatar gatorsmile Committed by Reynold Xin
Browse files

[SPARK-13840][SQL] Split Optimizer Rule ColumnPruning to ColumnPruning and EliminateOperator

#### What changes were proposed in this pull request?

Before this PR, two Optimizer rules `ColumnPruning` and `PushPredicateThroughProject` reverse each other's effects. Optimizer always reaches the max iteration when optimizing some queries. Extra `Project` are found in the plan. For example, below is the optimized plan after reaching 100 iterations:

```
Join Inner, Some((cast(id1#16 as bigint) = id1#18L))
:- Project [id1#16]
:  +- Filter isnotnull(cast(id1#16 as bigint))
:     +- Project [id1#16]
:        +- Relation[id1#16,newCol#17] JSON part: struct<>, data: struct<id1:int,newCol:int>
+- Filter isnotnull(id1#18L)
   +- Relation[id1#18L] JSON part: struct<>, data: struct<id1:bigint>
```

This PR splits the optimizer rule `ColumnPruning` to `ColumnPruning` and `EliminateOperators`

The issue becomes worse when having another rule `NullFiltering`, which could add extra Filters for `IsNotNull`. We have to be careful when introducing extra `Filter` if the benefit is not large enough. Another PR will be submitted by sameeragarwal to handle this issue.

cc sameeragarwal marmbrus

In addition, `ColumnPruning` should not push `Project` through non-deterministic `Filter`. This could cause wrong results. This will be put in a separate PR.

cc davies cloud-fan yhuai

#### How was this patch tested?

Modified the existing test cases.

Author: gatorsmile <gatorsmile@gmail.com>

Closes #11682 from gatorsmile/viewDuplicateNames.
parent 276c2d51
No related branches found
No related tags found
No related merge requests found
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment