Taras Bobrovytsky has posted comments on this change.

Change subject: IMPALA-5036: Parquet count star optimization
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Patch Set 5:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/6812/5/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java
File fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java:

PS5, Line 140:  This
             :   // scan does additional analysis in init() to determine 
whether it is correct to apply
             :   // the optimization.
> The optimization is applied if 2 things are true: the query block meets cer
An alternative approach that Alex and I are thinking about is passing in the 
agg info to the scan node so that all the checks would be done in one place.

One potential problem with this is that we need to access the SelectStmt too, 
in order to check that selectStmt.getTableRefs().size() == 1

I'm trying to figure out a way around this without having to pass the entire 
select statement to the scan node.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I536b85c014821296aed68a0c68faadae96005e62
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <tbobrovyt...@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com>
Gerrit-Reviewer: Lars Volker <l...@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <mar...@cloudera.com>
Gerrit-Reviewer: Mostafa Mokhtar <mmokh...@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovyt...@cloudera.com>
Gerrit-Reviewer: Zach Amsden <zams...@cloudera.com>
Gerrit-HasComments: Yes

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