Alex Behm has posted comments on this change. Change subject: IMPALA-4923: reduce memory transfer for selective scans ......................................................................
Patch Set 3: (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: ++num_output_batches; > Turns out it's the incorrect thing to do (found a bug in testing by test_me I think the idea was right, but the code wasn't quite implementing the idea (sorry for the distraction). If we increment the non-empty output batches at the end and modify the check to non_empty_output_batches > 0, then I think it can work. However, even that is suboptimal because what we really want to count are the non-compacted output batches because those are they only ones can still reference the tuple mem. Anyway, seems easy to forget a case and break this code, so let's worry about that potential improvement later. -- To view, visit http://gerrit.cloudera.org:8080/6949 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings 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]> Gerrit-HasComments: Yes
