c21 edited a comment on pull request #32210:
URL: https://github.com/apache/spark/pull/32210#issuecomment-826493892


   After skew join handling, the output partitioning is destroyed, but this 
approach keeps output partitioning. [Skew join handling will not be enabled if 
it introduces extra shuffle in plan 
now](https://github.com/apache/spark/blob/master/sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/OptimizeSkewedJoin.scala#L279).
 But I agree the change in AQE for skew join handling is more incremental and 
less intrusive. But as we see here, I don't see major intrusive API change here 
for this PR neither. I am just brainstorming the pros and cons, and I think we 
should pick the direction towards the eventual goal - enabling shuffled hash 
join by default.
   
   @cloud-fan - as you mentioned earlier, I agree with that (1). run-time 
sort-based fallback in shuffled hash join itself & (2). AQE skew join handling 
/ hybrid join features, to be orthogonal with each other. AQE is great to cover 
a lot of cases, but as we all know it has some limitations (listed some above 
and here).


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