### What changes were proposed in this pull request?
Currently `ShuffledHashJoin.outputPartitioning` inherits from `HashJoin.outputPartitioning`, which only preserves stream side partitioning (`HashJoin.scala`):
```
override def outputPartitioning: Partitioning = streamedPlan.outputPartitioning
```
This loses build side partitioning information, and causes extra shuffle if there's another join / group-by after this join.
Example:
```
withSQLConf(
SQLConf.AUTO_BROADCASTJOIN_THRESHOLD.key -> "50",
SQLConf.SHUFFLE_PARTITIONS.key -> "2",
SQLConf.PREFER_SORTMERGEJOIN.key -> "false") {
val df1 = spark.range(10).select($"id".as("k1"))
val df2 = spark.range(30).select($"id".as("k2"))
Seq("inner", "cross").foreach(joinType => {
val plan = df1.join(df2, $"k1" === $"k2", joinType).groupBy($"k1").count()
.queryExecution.executedPlan
assert(plan.collect { case _: ShuffledHashJoinExec => true }.size === 1)
// No extra shuffle before aggregate
assert(plan.collect { case _: ShuffleExchangeExec => true }.size === 2)
})
}
```
Current physical plan (having an extra shuffle on `k1` before aggregate)
```
*(4) HashAggregate(keys=[k1#220L], functions=[count(1)], output=[k1#220L, count#235L])
+- Exchange hashpartitioning(k1#220L, 2), true, [id=#117]
+- *(3) HashAggregate(keys=[k1#220L], functions=[partial_count(1)], output=[k1#220L, count#239L])
+- *(3) Project [k1#220L]
+- ShuffledHashJoin [k1#220L], [k2#224L], Inner, BuildLeft
:- Exchange hashpartitioning(k1#220L, 2), true, [id=#109]
: +- *(1) Project [id#218L AS k1#220L]
: +- *(1) Range (0, 10, step=1, splits=2)
+- Exchange hashpartitioning(k2#224L, 2), true, [id=#111]
+- *(2) Project [id#222L AS k2#224L]
+- *(2) Range (0, 30, step=1, splits=2)
```
Ideal physical plan (no shuffle on `k1` before aggregate)
```
*(3) HashAggregate(keys=[k1#220L], functions=[count(1)], output=[k1#220L, count#235L])
+- *(3) HashAggregate(keys=[k1#220L], functions=[partial_count(1)], output=[k1#220L, count#239L])
+- *(3) Project [k1#220L]
+- ShuffledHashJoin [k1#220L], [k2#224L], Inner, BuildLeft
:- Exchange hashpartitioning(k1#220L, 2), true, [id=#107]
: +- *(1) Project [id#218L AS k1#220L]
: +- *(1) Range (0, 10, step=1, splits=2)
+- Exchange hashpartitioning(k2#224L, 2), true, [id=#109]
+- *(2) Project [id#222L AS k2#224L]
+- *(2) Range (0, 30, step=1, splits=2)
```
This can be fixed by overriding `outputPartitioning` method in `ShuffledHashJoinExec`, similar to `SortMergeJoinExec`.
In addition, also fix one typo in `HashJoin`, as that code path is shared between broadcast hash join and shuffled hash join.
### Why are the changes needed?
To avoid shuffle (for queries having multiple joins or group-by), for saving CPU and IO.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Added unit test in `JoinSuite`.
Closes#29130 from c21/shj.
Authored-by: Cheng Su <chengsu@fb.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
fe07521c9e