wangyum opened a new pull request #31739:
URL: https://github.com/apache/spark/pull/31739
### What changes were proposed in this pull request?
These is a `Project` between `LocalLimit` and `Join` if `Join`'s output do
not match the `LocalLimit`'s output. For example:
```scala
spark.sql("create table t1(a int, b int, c int) using parquet")
spark.sql("create table t2(x int, y int, z int) using parquet")
spark.sql("select a from t1 left join t2 on a = x and b = y limit
5").explain("extended")
```
```
== Optimized Logical Plan ==
GlobalLimit 5
+- LocalLimit 5
+- Project [a#0]
+- Join LeftOuter, ((a#0 = x#3) AND (b#1 = y#4))
:- Project [a#0, b#1]
: +- Relation default.t1[a#0,b#1,c#2] parquet
+- Project [x#3, y#4]
+- Filter (isnotnull(x#3) AND isnotnull(y#4))
+- Relation default.t2[x#3,y#4,z#5] parquet
```
Thus, `LimitPushDown` can not optimize the query. This pr fix this issue.
### Why are the changes needed?
Fix bug.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Unit test.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
