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From "Alex Behm (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-3126: Conservative assignment of inner-join On-clause predicates.
Date Tue, 06 Dec 2016 22:00:56 GMT
Alex Behm has posted comments on this change.

Change subject: IMPALA-3126: Conservative assignment of inner-join On-clause predicates.
......................................................................


Patch Set 2:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/4982/2/testdata/workloads/functional-planner/queries/PlannerTest/outer-joins.test
File testdata/workloads/functional-planner/queries/PlannerTest/outer-joins.test:

Line 459: |  |  other predicates: a.tinyint_col < 10, b.tinyint_col > 20
> why is this correct? this only applies to matches, so a non-match wouldn't 
These are the "other predicates" and not the "other join predicates". The "other predicates"
are evaluated after the join result has been produced (according to the On-clause conditions).
The predicate discards all non-matches from the right side, so I think the results will be
correct.

I'm ok with assigning "foreign" predicates that reference outer-joined tuples to the originating
join. It's a simple change to the order of checks in Analyzer.

I don't think we should assign foreign predicates that don't reference outer-joined tuples
to the originating join because those can go into scans, so I'm worried about regressing perf.

I also changed the commit msg.


Line 892: # may not be assigned below the join materializing 'd'.
> are you saying it can be assigned to the join materializing d?
Yes. It would be correct to put the predicate in the "other predicates" of join 07.


Line 900: inner join functional.alltypes e
> are two joins/3 tables sufficient for this test case?
It has 4 joins and 5 tables and is exactly the same query as reported in the JIRA.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Idf45323ed9102ffb45c9d94a130ea3692286f215
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-HasComments: Yes

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