[
https://issues.apache.org/jira/browse/HIVE-24199?focusedWorklogId=490265&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-490265
]
ASF GitHub Bot logged work on HIVE-24199:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 24/Sep/20 15:17
Start Date: 24/Sep/20 15:17
Worklog Time Spent: 10m
Work Description: kasakrisz opened a new pull request #1525:
URL: https://github.com/apache/hive/pull/1525
### What changes were proposed in this pull request?
Fix incorrect result when subquey in exists contains limit.
### Why are the changes needed?
```
create table web_sales (ws_order_number int, ws_warehouse_sk int) stored as
orc;
insert into web_sales values
(1, 1),
(1, 2),
(2, 1),
(2, 2);
```
Query
```
select * from web_sales ws1
where exists (select 1 from web_sales ws2 where ws1.ws_order_number =
ws2.ws_order_number limit 1);
```
should return 4 four rows but returns only 2.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
New q test added.
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Issue Time Tracking
-------------------
Worklog Id: (was: 490265)
Remaining Estimate: 0h
Time Spent: 10m
> Incorrect result when subquey in exists contains limit
> ------------------------------------------------------
>
> Key: HIVE-24199
> URL: https://issues.apache.org/jira/browse/HIVE-24199
> Project: Hive
> Issue Type: Bug
> Reporter: Krisztian Kasa
> Assignee: Krisztian Kasa
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> {code:java}
> create table web_sales (ws_order_number int, ws_warehouse_sk int) stored as
> orc;
> insert into web_sales values
> (1, 1),
> (1, 2),
> (2, 1),
> (2, 2);
> select * from web_sales ws1
> where exists (select 1 from web_sales ws2 where ws1.ws_order_number =
> ws2.ws_order_number limit 1);
> 1 1
> 1 2
> {code}
> {code:java}
> CBO PLAN:
> HiveSemiJoin(condition=[=($0, $2)], joinType=[semi])
> HiveProject(ws_order_number=[$0], ws_warehouse_sk=[$1])
> HiveFilter(condition=[IS NOT NULL($0)])
> HiveTableScan(table=[[default, web_sales]], table:alias=[ws1])
> HiveProject(ws_order_number=[$0])
> HiveSortLimit(fetch=[1]) <-- This shouldn't be added
> HiveProject(ws_order_number=[$0])
> HiveFilter(condition=[IS NOT NULL($0)])
> HiveTableScan(table=[[default, web_sales]], table:alias=[ws2])
> {code}
> Limit n on the right side of the join reduces the result set coming from the
> right to only n record hence not all the ws_order_number values are included
> which leads to correctness issue.
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