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From "Alex Behm (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-3586: Implement union passthrough
Date Wed, 08 Mar 2017 18:42:51 GMT
Alex Behm has posted comments on this change.

Change subject: IMPALA-3586: Implement union passthrough
......................................................................


Patch Set 9:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/5816/9//COMMIT_MSG
Commit Message:

Line 15: as a precaution and for testing purposes.
> We made this decision with Alex in person a while ago. There are 2 reasons:
I agree that "blindly" adding query options is bad, but there are so many things that could
go wrong this optimizations. There is the issue of tuple-layout compatibility and of memory
management since we don't materialize any more. If there's a bug or a case we are missing
or even a resource regression (e.g. increased memory consumption), then we have no resource
without this query option.

The alternative is to test this to death until we are 100% confident there are no bugs. Still,
there are cases where we know the passthrough might lead to a higher peak memory consumption.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ia8f6d5062724ba5b78174c3227a7a796d10d8416
Gerrit-PatchSet: 9
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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