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From "Zach Amsden (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4939, IMPALA-4940: Decimal V2 multiplication
Date Wed, 27 Sep 2017 03:00:58 GMT
Zach Amsden has posted comments on this change. ( http://gerrit.cloudera.org:8080/7438 )

Change subject: IMPALA-4939, IMPALA-4940: Decimal V2 multiplication
......................................................................


Patch Set 6:

I totally agree about doing anything fancy as a followup.  In particular, I did not find anything
at all useful in AVX to help.  There is no vectored multiply large enough for this, and FMA
operations won't help either as they basically only help with precision loss on floating point
types.

Considering the perf difference is so extreme in some cases, I think we should strongly consider
either living with the broken behavior until we can come up with a solution, or else verifying
with users making use of the DECIMAL_V2 feature that this will not be a problem.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I37ad6232d7953bd75c18dc86e665b2b501a1ebe1
Gerrit-Change-Number: 7438
Gerrit-PatchSet: 6
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Michael Ho <kwho@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Zach Amsden <zamsden@cloudera.com>
Gerrit-Comment-Date: Wed, 27 Sep 2017 03:00:58 +0000
Gerrit-HasComments: No

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