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https://issues.apache.org/jira/browse/KUDU-1880?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon reassigned KUDU-1880:
---------------------------------
Assignee: Andrew Wong
> IS NULL predicates eliminate some NULL values
> ---------------------------------------------
>
> Key: KUDU-1880
> URL: https://issues.apache.org/jira/browse/KUDU-1880
> Project: Kudu
> Issue Type: Bug
> Affects Versions: 1.3.0
> Reporter: Joe McDonnell
> Assignee: Andrew Wong
> Priority: Blocker
>
> Impala is implementing IS NULL/IS NOT NULL Kudu predicates as part of
> IMPALA-4859 (see review: https://gerrit.cloudera.org/#/c/5958/ ). In testing,
> Kudu IS NULL is eliminating valid NULL values from results returned.
> Here is an example:
> select id, float_col from functional_kudu.alltypesagg where id < 10;
> | id | float_col |
> | 3 | 3.299999952316284 |
> | 7 | 7.699999809265137 |
> | 0 | NULL |
> | 6 | 6.599999904632568 |
> | 8 | 8.800000190734863 |
> | 9 | 9.899999618530273 |
> | 0 | NULL |
> | 1 | 1.100000023841858 |
> | 2 | 2.200000047683716 |
> | 4 | 4.400000095367432 |
> | 5 | 5.5 |
> Fetched 11 row(s) in 0.57s
> When adding an IS NULL condition on float_col, this does not return any rows.
> select id, float_col from functional_kudu.alltypesagg where id < 10 and
> float_col is null;
> Fetched 0 row(s) in 0.25s
> This is also true for other tables, such as functional_kudu.nulltable.
> select * from functional_kudu.nulltable;
> | a | b | c | d | e | f | g |
> | a | | NULL | NULL | NULL | ab | |
> Fetched 1 row(s) in 0.49s
> The following SQLs return no rows:
> select * from functional_kudu.nulltable where c is null;
> select * from functional_kudu.nulltable where d is null;
> select * from functional_kudu.nulltable where e is null;
> Impala statistics indicate that Kudu is not returning any rows. IS NOT NULL
> seems to work correctly.
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