Zoltan Borok-Nagy has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/11694 )

Change subject: IMPALA-7644: Hide Parquet page index writing with feature flag
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Patch Set 2:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/11694/2/be/src/exec/hdfs-parquet-table-writer.cc
File be/src/exec/hdfs-parquet-table-writer.cc:

http://gerrit.cloudera.org:8080/#/c/11694/2/be/src/exec/hdfs-parquet-table-writer.cc@705
PS2, Line 705: num_data_pages_
> Can you add a comment to this loop to explain why we don't use a range-base
Maybe we could just drop 'num_data_pages_' and call std::vector::resize(0) on 
'pages_' in Reset(). This should not affect the capacity of the vector, hence 
we would still save the cost of unnecessary deallocation/allocation.

std::vector::clear() should also work, but I'm a bit unsure about its effect on 
capacity:
http://www.cplusplus.com/reference/vector/vector/clear/
https://en.cppreference.com/w/cpp/container/vector/clear



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Ib4a9098a2085a385351477c715ae245d83bf1c72
Gerrit-Change-Number: 11694
Gerrit-PatchSet: 2
Gerrit-Owner: Zoltan Borok-Nagy <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Lars Volker <[email protected]>
Gerrit-Reviewer: Zoltan Borok-Nagy <[email protected]>
Gerrit-Comment-Date: Tue, 16 Oct 2018 21:44:14 +0000
Gerrit-HasComments: Yes

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