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https://issues.apache.org/jira/browse/HIVE-26135?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zoltan Haindrich updated HIVE-26135:
------------------------------------
    Description: 
right now I think the following is needed to trigger the issue:
* left outer join
* only select left hand side columns
* conditional which is using some udf
* the nullness of the udf is checked

repro sql; in case the conversion happens the row with 'a' will be missing
{code}
drop table if exists t;
drop table if exists n;

create table t(a string) stored as orc;
create table n(a string) stored as orc;

insert into t values ('a'),('1'),('2'),(null);
insert into n values ('a'),('b'),('1'),('3'),(null);


explain select n.* from n left outer join t on (n.a=t.a) where assert_true(t.a 
is null) is null;
explain select n.* from n left outer join t on (n.a=t.a) where cast(t.a as 
float) is null;


select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
null;
set hive.auto.convert.anti.join=false;
select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
null;

{code}

resultset with hive.auto.convert.anti.join enabled:
{code}
+------+
| n.a  |
+------+
| b    |
| 3    |
+------+
{code}

correct resultset with hive.auto.convert.anti.join disabled:
{code}
+-------+
|  n.a  |
+-------+
| a     |
| b     |
| 3     |
| NULL  |
+-------+
{code}


workaround could be to disable the feature:
{code}
set hive.auto.convert.anti.join=false;
{code}


  was:
right now I think the following is needed to trigger the issue:
* left outer join
* only select left hand side columns
* conditional which is using some udf
* the nullness of the udf is checked

repro sql; in case the conversion happens the row with 'a' will be missing
{code}
drop table if exists t;
drop table if exists n;

create table t(a string) stored as orc;
create table n(a string) stored as orc;

insert into t values ('a'),('1'),('2'),(null);
insert into n values ('a'),('b'),('1'),('3'),(null);


explain select n.* from n left outer join t on (n.a=t.a) where assert_true(t.a 
is null) is null;
explain select n.* from n left outer join t on (n.a=t.a) where cast(t.a as 
float) is null;


select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
null;
set hive.auto.convert.anti.join=false;
select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
null;

{code}



workaround could be to disable the feature:
{code}
set hive.auto.convert.anti.join=false;
{code}



> Invalid Anti join conversion may cause missing results
> ------------------------------------------------------
>
>                 Key: HIVE-26135
>                 URL: https://issues.apache.org/jira/browse/HIVE-26135
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Zoltan Haindrich
>            Assignee: Zoltan Haindrich
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> right now I think the following is needed to trigger the issue:
> * left outer join
> * only select left hand side columns
> * conditional which is using some udf
> * the nullness of the udf is checked
> repro sql; in case the conversion happens the row with 'a' will be missing
> {code}
> drop table if exists t;
> drop table if exists n;
> create table t(a string) stored as orc;
> create table n(a string) stored as orc;
> insert into t values ('a'),('1'),('2'),(null);
> insert into n values ('a'),('b'),('1'),('3'),(null);
> explain select n.* from n left outer join t on (n.a=t.a) where 
> assert_true(t.a is null) is null;
> explain select n.* from n left outer join t on (n.a=t.a) where cast(t.a as 
> float) is null;
> select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
> null;
> set hive.auto.convert.anti.join=false;
> select n.* from n left outer join t on (n.a=t.a) where cast(t.a as float) is 
> null;
> {code}
> resultset with hive.auto.convert.anti.join enabled:
> {code}
> +------+
> | n.a  |
> +------+
> | b    |
> | 3    |
> +------+
> {code}
> correct resultset with hive.auto.convert.anti.join disabled:
> {code}
> +-------+
> |  n.a  |
> +-------+
> | a     |
> | b     |
> | 3     |
> | NULL  |
> +-------+
> {code}
> workaround could be to disable the feature:
> {code}
> set hive.auto.convert.anti.join=false;
> {code}



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