Adar Dembo has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/13987 )

Change subject: KUDU-2854 short circuit predicates on dictionary-coded columns
......................................................................


Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/13987/1/src/kudu/tablet/delta_store.cc
File src/kudu/tablet/delta_store.cc:

http://gerrit.cloudera.org:8080/#/c/13987/1/src/kudu/tablet/delta_store.cc@494
PS1, Line 494:   return may_have_deltas_ ?
             :       (!updates_by_col_[col_idx].empty() || !deleted_.empty() || 
!reinserted_.empty()) : false;
> Hmmm, the code here is close to O(1). It is different with KUDU-2381 who ha
Wouldn't it be just a single memset across all e.g. 35 bytes? Internally memset 
operates on 8 bytes at a time, then one operation at the end for the remaining 
<8 bytes.

In his commit description, Zhang Yao talks about running a benchmark; perhaps 
you could reach out to him and ask for more specifics?



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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Id348583cc7d85773e8f32a189f4344d7a36a30b6
Gerrit-Change-Number: 13987
Gerrit-PatchSet: 1
Gerrit-Owner: helifu <[email protected]>
Gerrit-Reviewer: Adar Dembo <[email protected]>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: helifu <[email protected]>
Gerrit-Comment-Date: Tue, 13 Aug 2019 07:34:15 +0000
Gerrit-HasComments: Yes

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