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https://issues.apache.org/jira/browse/DRILL-7104?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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benj updated DRILL-7104:
------------------------
    Affects Version/s: 1.16.0
                       1.17.0

> Change of data type when parquet with multiple fragment
> -------------------------------------------------------
>
>                 Key: DRILL-7104
>                 URL: https://issues.apache.org/jira/browse/DRILL-7104
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Storage - Parquet
>    Affects Versions: 1.15.0, 1.16.0, 1.17.0
>            Reporter: benj
>            Priority: Major
>         Attachments: DRILL-7104_ErrorNumberFormatException_20190322.log
>
>
> When creating a Parquet with a column filled only with "CAST(NULL AS 
> VARCHAR)", if the parquet has several fragment, the type is read like INT 
> instead of VARCHAR.
> First, create +Parquet with only one fragment+ - all is fine (the type of 
> "demo" is correct).
> {code:java}
> CREATE TABLE ....`nobug` AS 
>  (SELECT CAST(NULL AS VARCHAR) AS demo
>   , md5(cast(rand() AS VARCHAR) AS jam 
>   FROM ....`onebigfile` LIMIT 1000000));
> +-----------+----------------------------+
> | Fragment  | Number of records written  |
> +-----------+----------------------------+
> | 0_0       | 10000000                   |
> SELECT drilltypeof(demo) AS goodtype FROM ....`bug` LIMIT 1;
> +--------------------+
> | goodtype           |
> +--------------------+
> | VARCHAR            |
> {code}
> Second, create +Parquet with at least 2 fragments+ - the type of "demo" 
> change to INT
> {code:java}
> CREATE TABLE ....`bug` AS 
> ((SELECT CAST(NULL AS VARCHAR) AS demo
>   ,md5(CAST(rand() AS VARCHAR)) AS jam 
>   FROM ....`onebigfile` LIMIT 1000000) 
>  UNION 
>  (SELECT CAST(NULL AS VARCHAR) AS demo
>   ,md5(CAST(rand() AS VARCHAR)) AS jam
>   FROM ....`onebigfile` LIMIT 1000000));
> +-----------+----------------------------+
> | Fragment  | Number of records written  |
> +-----------+----------------------------+
> | 1_1       | 1000276                    |
> | 1_0       | 999724                     |
> SELECT drilltypeof(demo) AS badtype FROM ....`bug` LIMIT 1;
> +--------------------+
> | badtype            |
> +--------------------+
> | INT                |{code}
> The change of type is really terrible...
>  
>  
>  



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