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https://issues.apache.org/jira/browse/HIVE-26135?focusedWorklogId=755848&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-755848
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ASF GitHub Bot logged work on HIVE-26135:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 12/Apr/22 15:44
Start Date: 12/Apr/22 15:44
Worklog Time Spent: 10m
Work Description: kgyrtkirk opened a new pull request, #3205:
URL: https://github.com/apache/hive/pull/3205
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### What changes were proposed in this pull request?
restricts the optimization to only happen in case `X IS NULL` is present and
`X` is Strong and there is no `CAST` in `X`.
...in fact in Hive `CAST` is not `Strong`; but its not possible to change
how `CAST` is treated in the current version of Calcite
### Why are the changes needed?
without this patch incorrect optimaztion may happen
### Does this PR introduce _any_ user-facing change?
not really - it only makes the optimization less zealous
### How was this patch tested?
a qtest was added to cover for it
Issue Time Tracking
-------------------
Worklog Id: (was: 755848)
Remaining Estimate: 0h
Time Spent: 10m
> 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
> 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}
> workaround could be to disable the feature:
> {code}
> set hive.auto.convert.anti.join=false;
> {code}
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