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https://issues.apache.org/jira/browse/HIVE-26524?focusedWorklogId=811279&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-811279
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ASF GitHub Bot logged work on HIVE-26524:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 22/Sep/22 15:25
            Start Date: 22/Sep/22 15:25
    Worklog Time Spent: 10m 
      Work Description: kasakrisz commented on code in PR #3588:
URL: https://github.com/apache/hive/pull/3588#discussion_r977796570


##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/ASTConverter.java:
##########
@@ -121,7 +127,83 @@ public static ASTNode convert(final RelNode relNode, 
List<FieldSchema> resultSch
     return c.convert();
   }
 
+  //    TOK_QUERY
+  //      TOK_INSERT
+  //         TOK_DESTINATION
+  //            TOK_DIR
+  //               TOK_TMP_FILE
+  //         TOK_SELECT
+  //            TOK_SELEXPR
+  //               TOK_FUNCTION
+  //                  TOK_<type>
+  //                  TOK_NULL
+  //               alias0
+  //            ...
+  //            TOK_SELEXPR
+  //               TOK_FUNCTION
+  //                  TOK_<type>
+  //                  TOK_NULL
+  //               aliasn
+  //         TOK_LIMIT
+  //            0
+  //            0
+  private static ASTNode emptyPlan(RelDataType dataType) {

Review Comment:
   Added UT.





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

    Worklog Id:     (was: 811279)
    Time Spent: 3h 10m  (was: 3h)

> 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: 3h 10m
>  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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