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From "Skye Wanderman-Milne (Code Review)" <ger...@cloudera.org>
Subject [Impala-CR](cdh5-trunk) IMPALA-3311: fix string data coming out of aggs in subplans
Date Wed, 11 May 2016 00:44:34 GMT
Skye Wanderman-Milne has posted comments on this change.

Change subject: IMPALA-3311: fix string data coming out of aggs in subplans
......................................................................


Patch Set 1:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/2929/1/be/src/exec/partitioned-aggregation-node.cc
File be/src/exec/partitioned-aggregation-node.cc:

Line 370:   for (int i = 0; i < aggregate_evaluators_.size(); ++i) {
> This is a pretty big block of code, I think it'd be more readable if it was
I moved the string copying code to its own function. Lemme know if you think I should factor
out more.


Line 374:     if (IsInSubplan()) {
> Makes sense. Is it worth adding a targeted perf query to check we don't reg
I'm having trouble writing a good query that really isolates this effect and isn't too complicated.
I have a query where the effect is noticeable, but the subplan still dominates the time (2s
vs 2.4s locally, but the non-subplan aggregation time doubles). I'll post what I have.


Line 380:       for (int i = first_row_idx; i < row_batch->num_rows(); ++i, ++row) {
> You could use the new RowBatch::Iterator. I think you're doing exactly what
Done


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Gerrit-MessageType: comment
Gerrit-Change-Id: Iada891504c261ba54f4eb8c9d7e4e5223668d7b9
Gerrit-PatchSet: 1
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Skye Wanderman-Milne <skye@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Skye Wanderman-Milne <skye@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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