Zoltan Borok-Nagy has posted comments on this change. ( http://gerrit.cloudera.org:8080/9090 )
Change subject: IMPALA-5903: Inconsistent specification of result set and result set metadata ...................................................................... Patch Set 1: Thanks for looking at this. Now that I've run all the tests it turned out COMPUTE STATS in most cases does return a result set, but in some rare cases (COMPUTE INCREMENTAL STATS with no new partitions) it doesn't return anything. Fortunately both cases can be identified at parse-time, so we can set the correct schema in Frontend.java. As far as I can tell the current behavior is that when the statement can produce meaningful information about its execution, we put this information into the result set. I don't think we want to throw away this information, so the appropriate behavior might be to always return a 'summary'. Do you think would it be OK? About breaking some clients: I think the current behavior is rather a bug. We tell the client that the statement doesn't have a result set, but then we magically return one. The clients have to know which statements return a result set and which statements don't. As Tim pointed out it is hard to imagine that clients rely on invalid metadata, but it's possible. So, maybe this change could go into Impala v3 / CDH6 only. Anyway, I'll upload a new PS with minor fixes, and after further discussion we'll see how to move forward. -- To view, visit http://gerrit.cloudera.org:8080/9090 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ic542fb8e49e850052416ac663ee329ee3974e3b9 Gerrit-Change-Number: 9090 Gerrit-PatchSet: 1 Gerrit-Owner: Zoltan Borok-Nagy <borokna...@cloudera.com> Gerrit-Reviewer: Dimitris Tsirogiannis <dtsirogian...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Reviewer: Zoltan Borok-Nagy <borokna...@cloudera.com> Gerrit-Comment-Date: Tue, 23 Jan 2018 15:30:45 +0000 Gerrit-HasComments: No
