[
https://issues.apache.org/jira/browse/HIVE-26524?focusedWorklogId=813808&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-813808
]
ASF GitHub Bot logged work on HIVE-26524:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Sep/22 22:56
Start Date: 30/Sep/22 22:56
Worklog Time Spent: 10m
Work Description: difin commented on code in PR #3588:
URL: https://github.com/apache/hive/pull/3588#discussion_r984991177
##########
ql/src/test/results/clientpositive/llap/subquery_ALL.q.out:
##########
@@ -413,8 +413,7 @@ POSTHOOK: Input: default@part
POSTHOOK: Input: default@part_null_n0
#### A masked pattern was here ####
26
-Warning: Shuffle Join MERGEJOIN[37][tables = [$hdt$_1, $hdt$_2]] in Stage
'Reducer 3' is a cross product
-Warning: Shuffle Join MERGEJOIN[38][tables = [$hdt$_1, $hdt$_2, $hdt$_0]] in
Stage 'Reducer 4' is a cross product
+Warning: Shuffle Join MERGEJOIN[22][tables = [$hdt$_0, $hdt$_1]] in Stage
'Reducer 2' is a cross product
Review Comment:
Will these changes work for insert statements that produce zero records
also, or only for select queries?
I am asking because there is a ticket
https://issues.apache.org/jira/browse/HIVE-24466 - "insert queries should not
launch job when condition in the query would output 0 rows", I was wondering it
these changes are a fix for that ticket too.
Issue Time Tracking
-------------------
Worklog Id: (was: 813808)
Time Spent: 5h 20m (was: 5h 10m)
> 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 20m
> 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}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
