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From "Henry Robinson (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-2494: Support for byte array-encoded decimals in Parquet scanner
Date Thu, 17 Nov 2016 00:32:56 GMT
Henry Robinson has posted comments on this change.

Change subject: IMPALA-2494: Support for byte array-encoded decimals in Parquet scanner
......................................................................


Patch Set 1:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/5115/1//COMMIT_MSG
Commit Message:

Line 21:  * Tested computing SUM(col) for 1 billion distinct dictionary-encoded
> Can also verify on plain encoding? Seems like that would be the extreme cas
Can do - but where would that extra slowness really come from? I would have thought decoding
1 billion values would represent a large portion of the execution time of such a simple query,
and if the proportion is really that small I'm inclined to worry even less about the perf
differential.


Line 23:  * No performance difference measured by introduction of extra
> Did you run this with num_scanner_threads=1 or even better mt_dop=1?
No, but I can do. What do you expect to change?


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Gerrit-MessageType: comment
Gerrit-Change-Id: If95171e65aa48f08b08b8e87f4555dc75e867977
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Henry Robinson <henry@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Henry Robinson <henry@cloudera.com>
Gerrit-HasComments: Yes

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