Riza Suminto has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/18711 )

Change subject: IMPALA-11418: The only select constant statement need not to 
spool results
......................................................................


Patch Set 7:

> Patch Set 7:
>
> > Patch Set 7:
> >
> > I found another way to optimize this. We can disable result spooling for 
> > small queries and modify in 
> > https://github.com/apache/impala/blob/f1420ae51b2e00ad093be64a0d2135ca36aa6514/fe/src/main/java/org/apache/impala/planner/Planner.java#L663-L667
> > Is this way better?
>
> Or use the method SelectStmt#returnsExactlyOneRow, if the query return one 
> row disable result spooling.

If checkForSmallQueryOptimization is on, it implies that query will run in 
single backend only. There might be a case later where we can extend this spool 
disabling for large query that return only single row only. Checking 
SelectStmt#returnsExactlyOneRow is probably a better alternative.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Icd4d73c21106048df68a270cf03d4abd56bd3aac
Gerrit-Change-Number: 18711
Gerrit-PatchSet: 7
Gerrit-Owner: Xianqing He <[email protected]>
Gerrit-Reviewer: Aman Sinha <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Quanlong Huang <[email protected]>
Gerrit-Reviewer: Riza Suminto <[email protected]>
Gerrit-Reviewer: Xianqing He <[email protected]>
Gerrit-Comment-Date: Thu, 25 Aug 2022 22:13:10 +0000
Gerrit-HasComments: No

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