Tim Armstrong has posted comments on this change.

Change subject: IMPALA-4923: reduce memory transfer for selective scans
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Patch Set 3:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/6949/3/be/src/exec/parquet-scratch-tuple-batch.h
File be/src/exec/parquet-scratch-tuple-batch.h:

Line 102:     ++num_output_batches;
> I think the idea was right, but the code wasn't quite implementing the idea
I looked again and realised we don't even need to track num_output_batches. 
num_tuples_transferred > num_to_commit implies that tuples were transferred to 
a previous batch.

It's enough of a simplification it seems worth doing.


http://gerrit.cloudera.org:8080/#/c/6949/4/be/src/exec/parquet-scratch-tuple-batch.h
File be/src/exec/parquet-scratch-tuple-batch.h:

PS4, Line 142:   Tuple* uncompacted_tuple = row->GetTuple(0);
> FOREACH_ROW() ?
I looked earlier - the rows aren't committed to the batch yet so FOREACH_ROW 
doesn't work for this case.


PS4, Line 155: }
> not needed ?
Yep, and also the ones below.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I3773dc63c498e295a2c1386a15c5e69205e747ea
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Michael Ho <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
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