[jira] [Work logged] (HIVE-26524) Use Calcite to remove sections of a query plan known never produces rows

[ASF GitHub Bot (Jira)]

     [ 
https://issues.apache.org/jira/browse/HIVE-26524?focusedWorklogId=814035&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-814035
 ]

ASF GitHub Bot logged work on HIVE-26524:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 05/Oct/22 20:03
            Start Date: 05/Oct/22 20:03
    Worklog Time Spent: 10m 
      Work Description: kasakrisz commented on code in PR #3588:
URL: https://github.com/apache/hive/pull/3588#discussion_r985692371


##########
ql/src/test/results/clientpositive/llap/ppd_udf_col.q.out:
##########
@@ -80,22 +80,9 @@ STAGE DEPENDENCIES:
 STAGE PLANS:
   Stage: Stage-0
     Fetch Operator
-      limit: -1
+      limit: 0
       Processor Tree:
-        TableScan
-          alias: src
-          filterExpr: (UDFToDouble(key) = 100.0D) (type: boolean)
-          Filter Operator
-            predicate: (UDFToDouble(key) = 100.0D) (type: boolean)
-            Limit
-              Number of rows: 0
-              Select Operator
-                expressions: key (type: string)
-                outputColumnNames: _col0
-                Select Operator
-                  expressions: _col0 (type: string), rand() (type: double), 
'4' (type: string)
-                  outputColumnNames: _col0, _col1, _col2
-                  ListSink
+        ListSink

Review Comment:
   The original empty plan has a TS on the `dummy_table` but this is converted 
to a Fetch task.
   ```
   STAGE PLANS:
     Stage: Stage-0
       Fetch Operator
         limit: 0
         Processor Tree:
           ListSink
   ```





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

    Worklog Id:     (was: 814035)
    Time Spent: 6h  (was: 5h 50m)

> 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: 6h
>  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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