Riza Suminto has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/15370 )

Change subject: IMPALA-6636: Use async IO in ORC scanner
......................................................................


Patch Set 21:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/15370/21/be/src/exec/hdfs-orc-scanner.cc
File be/src/exec/hdfs-orc-scanner.cc:

http://gerrit.cloudera.org:8080/#/c/15370/21/be/src/exec/hdfs-orc-scanner.cc@165
PS21, Line 165:       return false;
> Why we exclude these index streams? They will be read when we add SearchArg
We might exclude the index streams here because we're not sure about their read 
pattern.
For ColumnRange standpoint, we expect that streams eligible for async io is 
only read forward (never seek backward).
I will double check about this with Csaba.


http://gerrit.cloudera.org:8080/#/c/15370/21/be/src/exec/hdfs-orc-scanner.cc@484
PS21, Line 484:     unique_ptr<orc::InputStream> input_stream(input_stream_);
> Should we use shared_ptr instead?
I believe it is unique_ptr here because orc::createReader first parameter ask 
for unique_ptr<InputStream> type.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I348ad9e55f0cae7dff0d74d941b026dcbf5e4074
Gerrit-Change-Number: 15370
Gerrit-PatchSet: 21
Gerrit-Owner: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Kurt Deschler <[email protected]>
Gerrit-Reviewer: Quanlong Huang <[email protected]>
Gerrit-Reviewer: Riza Suminto <[email protected]>
Gerrit-Comment-Date: Tue, 18 Jan 2022 18:36:49 +0000
Gerrit-HasComments: Yes

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