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From "Tim Armstrong (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4923: reduce memory transfer for selective scans
Date Wed, 24 May 2017 21:05:41 GMT
Tim Armstrong has posted comments on this change.

Change subject: IMPALA-4923: reduce memory transfer for selective scans
......................................................................


Patch Set 5:

(1 comment)

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:   void FinalizeTupleTransfer(RowBatch* dst_batch, int num_to_commit) {
> Done. Yeah that's a more precise thing to do.
Turns out it's the incorrect thing to do (found a bug in testing by test_mem_usage_scaling).
The problem is if you have a non-empty output batch, followed by an empty one, this is 1,
but it's actually invalid to reuse the tuple memory, because the first batch is still referencing
it.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I3773dc63c498e295a2c1386a15c5e69205e747ea
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Mostafa Mokhtar <mmokhtar@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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