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https://issues.apache.org/jira/browse/HIVE-26524?focusedWorklogId=814020&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-814020
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ASF GitHub Bot logged work on HIVE-26524:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 05/Oct/22 20:02
            Start Date: 05/Oct/22 20:02
    Worklog Time Spent: 10m 
      Work Description: zabetak commented on code in PR #3588:
URL: https://github.com/apache/hive/pull/3588#discussion_r985676478


##########
ql/src/test/results/clientpositive/llap/masking_10.q.out:
##########
@@ -137,9 +136,7 @@ STAGE PLANS:
     Tez
 #### A masked pattern was here ####
       Edges:
-        Reducer 2 <- Map 1 (CUSTOM_SIMPLE_EDGE), Reducer 4 (CUSTOM_SIMPLE_EDGE)
-        Reducer 3 <- Map 1 (SIMPLE_EDGE), Reducer 2 (SIMPLE_EDGE)
-        Reducer 4 <- Map 1 (SIMPLE_EDGE)
+        Reducer 2 <- Map 1 (SIMPLE_EDGE), Map 3 (SIMPLE_EDGE)

Review Comment:
   Thanks for clarifying. I forgot about the query rewrites due to masking.





Issue Time Tracking
-------------------

    Worklog Id:     (was: 814020)
    Time Spent: 5h 50m  (was: 5h 40m)

> Use Calcite to remove sections of a query plan known never produces rows
> ------------------------------------------------------------------------
>
>                 Key: HIVE-26524
>                 URL: https://issues.apache.org/jira/browse/HIVE-26524
>             Project: Hive
>          Issue Type: Improvement
>          Components: CBO
>            Reporter: Krisztian Kasa
>            Assignee: Krisztian Kasa
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 5h 50m
>  Remaining Estimate: 0h
>
> Calcite has a set of rules to remove sections of a query plan known never 
> produces any rows. In some cases the whole plan can be removed. Such plans 
> are represented with a single {{Values}} operators with no tuples. ex.:
> {code:java}
> select y + 1 from (select a1 y, b1 z from t1 where b1 > 10) q WHERE 1=0
> {code}
> {code:java}
> HiveValues(tuples=[[]])
> {code}
> Other cases when plan has outer join or set operators some branches can be 
> replaced with empty values moving forward in some cases the join/set operator 
> can be removed
> {code:java}
> select a2, b2 from t2 where 1=0
> union
> select a1, b1 from t1
> {code}
> {code:java}
> HiveAggregate(group=[{0, 1}])
>   HiveTableScan(table=[[default, t1]], table:alias=[t1])
> {code}



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