alamb commented on a change in pull request #1402:
URL: https://github.com/apache/arrow-datafusion/pull/1402#discussion_r763498003
##########
File path: datafusion/src/logical_plan/plan.rs
##########
@@ -38,7 +38,7 @@ pub enum JoinType {
Inner,
/// Left Join
Left,
- /// Right Join
+ /// Right Join: will be transferred to Left Join
Review comment:
This is a good idea @xudong963 -- I do think it will keep things
somewhat easier to handle.
If we are going to make this change, I think we should remove the `Right`
enum value from `JoinType`
The only possibly issue I can see with this change is that is may complicate
the join implementation (which needs to distinguish between both which relation
needs to be preserved and which gets hashed)
Using `Left` and `Right` enum values might allow us to maintain that
distinction
So for example
```
A LEFT JOIN B --> Means preserve B, hash B
B LEFT JOIN A --> Means preserve A, hash A
B RIGHT JOIN A --> Means preserve B, hash A
A RIGHT JOIN B --> Means preserve A, hash B
```
Thoughts @Dandandan ?
##########
File path: datafusion/src/logical_plan/plan.rs
##########
@@ -38,7 +38,7 @@ pub enum JoinType {
Inner,
/// Left Join
Left,
- /// Right Join
+ /// Right Join: will be transferred to Left Join
Review comment:
This is a good idea @xudong963 -- I do think it will keep things
somewhat easier to handle.
If we are going to make this change, I think we should remove the `Right`
enum value from `JoinType`
The only possibly issue I can see with this change is that is may complicate
the join implementation (which needs to distinguish between both which relation
needs to be preserved and which gets hashed)
Using `Left` and `Right` enum values might allow us to maintain that
distinction
So for example
```
A LEFT JOIN B --> Means preserve B, hash B
B LEFT JOIN A --> Means preserve A, hash A
B RIGHT JOIN A --> Means preserve B, hash A
A RIGHT JOIN B --> Means preserve A, hash B
```
Thoughts @Dandandan ?
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