[jira] [Created] (SPARK-25797) Views created via 2.1 cannot be read via 2.2+

["Chenxiao Mao (JIRA)" <ji...@apache.org>]

Chenxiao Mao created SPARK-25797:
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             Summary: Views created via 2.1 cannot be read via 2.2+
                 Key: SPARK-25797
                 URL: https://issues.apache.org/jira/browse/SPARK-25797
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 2.3.2, 2.3.1, 2.3.0, 2.2.2, 2.2.1, 2.2.0
            Reporter: Chenxiao Mao


We ran into this issue when we update our Spark from 2.1 to 2.3. Below's a simple example to reproduce the issue.

Create views via Spark 2.1

 
|create view v1 as
select (cast(1 as decimal(18,0)) + cast(1 as decimal(18,0))) c1;|

 

Query views via Spark 2.3
|{{select * from v1;}}
{{Error in query: Cannot up cast `c1` from decimal(20,0) to c1#3906: decimal(19,0) as it may truncate}}|

 

After investigation, we found that this is because when a view is created via Spark 2.1, the expanded text is saved instead of the original text. Unfortunately, the blow expanded text is buggy.
|spark-sql> desc extended v1;
c1 decimal(19,0) NULL
# Detailed Table Information
Database default
Table v1
Type VIEW
View Text SELECT `gen_attr_0` AS `c1` FROM (SELECT (CAST(CAST(1 AS DECIMAL(18,0)) AS DECIMAL(19,0)) + CAST(CAST(1 AS DECIMAL(18,0)) AS DECIMAL(19,0))) AS `gen_attr_0`) AS gen_subquery_0|

We can see that c1 is decimal(19,0), however in the expanded text there is decimal(19,0) + decimal(19,0) which results in decimal(20,0). Since Spark 2.2, decimal(20,0) in query is not allowed to cast to view definition column decimal(19,0). ([https://github.com/apache/spark/pull/16561])

I further tested other decimal calculations. Only add/subtract has this issue.

Create views via 2.1:
|create view v1 as
select (cast(1 as decimal(18,0)) + cast(1 as decimal(18,0))) c1;
create view v2 as
select (cast(1 as decimal(18,0)) - cast(1 as decimal(18,0))) c1;
create view v3 as
select (cast(1 as decimal(18,0)) * cast(1 as decimal(18,0))) c1;
create view v4 as
select (cast(1 as decimal(18,0)) / cast(1 as decimal(18,0))) c1;
create view v5 as
select (cast(1 as decimal(18,0)) % cast(1 as decimal(18,0))) c1;
create view v6 as
select cast(1 as decimal(18,0)) c1
union
select cast(1 as decimal(19,0)) c1;|

Query views via Spark 2.3
|select * from v1;
Error in query: Cannot up cast `c1` from decimal(20,0) to c1#3906: decimal(19,0) as it may truncate
select * from v2;
Error in query: Cannot up cast `c1` from decimal(20,0) to c1#3909: decimal(19,0) as it may truncate
select * from v3;
1
select * from v4;
1
select * from v5;
0
select * from v6;
1|

 



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