maryannxue commented on issue #23759: [SPARK-26840][SQL] Avoid cost-based join reorder in presence of join hints URL: https://github.com/apache/spark/pull/23759#issuecomment-462912292 @dongjoon-hyun: Just to be clear: the hint behaviors were not clearly documented or well tested. One of the reasons for this whole hint refactoring was to make optimizer work better when hints are present (rules could otherwise be stopped by this trivial `ResolveHint` node). I had wanted to make join re-ordering work with hints as well, but then found out we had to hold back given the duplicate expr id issue, and it'd probably be a good idea to define the behavior clearly first. Back to "important things" I mentioned earlier, I think it would have been great if you could have pointed out the correctness problem in my first check-in [98be895](https://github.com/apache/spark/commit/98be8953c75c026c1cb432cc8f66dd312feed0c6). Assume that's what reviewers should do before all other things. And as to this PR, I think it'd be great to refine the code comments here as well, since it took me a little while to figure out what `OrderedJoin` is really for ( guess the same for you ;) )
---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
