Tim Armstrong has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/11440 )

Change subject: IMPALA-7351: Improve memory estimates for Kudu Scan Nodes
......................................................................


Patch Set 2:

(6 comments)

Just a few more cleanup and test suggestions

http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/KuduScanNode.java
File fe/src/main/java/org/apache/impala/planner/KuduScanNode.java:

http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/KuduScanNode.java@284
PS2, Line 284:     int perHostScanRanges = (int) Math.ceil(((double) 
scanRangeSpecs_
Can we factor out the per-host scan range calculation into a helper? I know 
it's short but the logic isn't trivial and I think we expect it to be identical 
between the scan node implementations (unless something changes in future).


http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/KuduScanNode.java@296
PS2, Line 296:     .setMemEstimateBytes(mem_estimate_per_thread * 
maxScannerThreads)
This new indentation seems weird to me.


http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/ScanNode.java
File fe/src/main/java/org/apache/impala/planner/ScanNode.java:

http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/ScanNode.java@232
PS2, Line 232: ComputeMaxNumberOfScannerThreads
Initial letter of method name should be lower-case in java.


http://gerrit.cloudera.org:8080/#/c/11440/2/fe/src/main/java/org/apache/impala/planner/ScanNode.java@237
PS2, Line 237:       maxScannerThreads = 1;
We can just return early here (and eliminate the nesting of the else branch.


http://gerrit.cloudera.org:8080/#/c/11440/1/testdata/workloads/functional-planner/queries/PlannerTest/kudu-selectivity.test
File 
testdata/workloads/functional-planner/queries/PlannerTest/kudu-selectivity.test:

PS1:
> Yup, my main intention was to just keep track of how the estimates change o
Yeah, that seems fine to update then, no reason to have things diverge :)


http://gerrit.cloudera.org:8080/#/c/11440/2/testdata/workloads/functional-planner/queries/PlannerTest/resource-requirements.test
File 
testdata/workloads/functional-planner/queries/PlannerTest/resource-requirements.test:

http://gerrit.cloudera.org:8080/#/c/11440/2/testdata/workloads/functional-planner/queries/PlannerTest/resource-requirements.test@5256
PS2, Line 5256: select * from functional_kudu.alltypes
Can you also add a scan of a single column and a scan of count(*) and a scan of 
an unpartitioned table like tpch_kudu.nation, which I think should only be 
scanned on one node with one thread.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: If9bb52530271b0bff91311a67d222a2e9fac1229
Gerrit-Change-Number: 11440
Gerrit-PatchSet: 2
Gerrit-Owner: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Comment-Date: Mon, 24 Sep 2018 16:14:03 +0000
Gerrit-HasComments: Yes

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