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 16:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/15370/16/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java
File fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java:

http://gerrit.cloudera.org:8080/#/c/15370/16/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java@2179
PS16, Line 2179:     if (orcAsyncRead) 
columnByteSizes.add(DEFAULT_COLUMN_SCAN_RANGE_RESERVATION);
I think we can do better on counting min mem reservation here and other places 
for orcAsyncRead.
DEFAULT_COLUMN_SCAN_RANGE_RESERVATION is 4MB, and by keep appending this much 
per stream, we potentially going to over provision memory by a lot. Instead, we 
can split this 4MB allocation to all streams that belong to the column.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I348ad9e55f0cae7dff0d74d941b026dcbf5e4074
Gerrit-Change-Number: 15370
Gerrit-PatchSet: 16
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: Wed, 08 Dec 2021 17:56:35 +0000
Gerrit-HasComments: Yes

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