[jira] [Created] (DRILL-7104) Change of data type when parquet with multiple fragment

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

benj created DRILL-7104:
---------------------------

             Summary: 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
            Reporter: benj


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 ....`bug` 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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