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From "Jim Apple (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5347: Parquet scanner microoptimizations
Date Tue, 23 May 2017 18:17:33 GMT
Jim Apple has posted comments on this change.

Change subject: IMPALA-5347: Parquet scanner microoptimizations
......................................................................


Patch Set 6:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/6950/5/be/src/exec/parquet-column-readers.cc
File be/src/exec/parquet-column-readers.cc:

Line 315:   /// Use __restrict__ so that the compiler knows that it is safe to cache member
> We compile with -fno-strict-alias so there's no type-based alias analysis a
And you can't __restrict__ num_values and pool because they actually can alias?


Line 489:     void* slot = tuple->GetSlot(tuple_offset_);
> Seems like a good idea. I'm not sure if we really depend on it - generally 
alignas(T)?

http://en.cppreference.com/w/cpp/language/alignas


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Gerrit-MessageType: comment
Gerrit-Change-Id: I49ec523a65542fdbabd53fbcc4a8901d769e5cd5
Gerrit-PatchSet: 6
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Jim Apple <jbapple-impala@apache.org>
Gerrit-Reviewer: Mostafa Mokhtar <mmokhtar@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: anujphadke <aphadke@cloudera.com>
Gerrit-HasComments: Yes

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