Aman Sinha has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/16723 )

Change subject: IMPALA-10314: Optimize planning time for simple limits
......................................................................


Patch Set 5:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/16723/4/testdata/workloads/functional-planner/queries/PlannerTest/optimize-simple-limit.test
File 
testdata/workloads/functional-planner/queries/PlannerTest/optimize-simple-limit.test:

http://gerrit.cloudera.org:8080/#/c/16723/4/testdata/workloads/functional-planner/queries/PlannerTest/optimize-simple-limit.test@241
PS4, Line 241:  limit 1
> Yeah, that is a tricky issue.
I went with a simple approach of skipping the empty files when we are iterating 
over the file descriptors and only increment the count for the non-empty files. 
The determination of empty vs non-empty also depends on the file system 
type..so there's a check for that.  PS 5 has the latest changes.   I also 
modified the commit message accordingly.

I haven't added new tests for this since I am not quite sure if we have a data 
set that has such mixed empty and non-empty files per partition.  If you guys 
think it is important to test that, I am open to adding one.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I9d6a79263bc092e0f3e9a1d72da5618f3cc35574
Gerrit-Change-Number: 16723
Gerrit-PatchSet: 5
Gerrit-Owner: Aman Sinha <[email protected]>
Gerrit-Reviewer: Aman Sinha <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Qifan Chen <[email protected]>
Gerrit-Reviewer: Shant Hovsepian <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Comment-Date: Thu, 19 Nov 2020 02:17:40 +0000
Gerrit-HasComments: Yes

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