[DRILL-6588] System table columns incorrectly marked as non-nullable

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.13.0
• Fix Version/s: 1.14.0
• Component/s: Metadata
• Labels: ready-to-commit
• Assignee: Kunal Khatua
• Reporter: Aman Sinha
• Reviewer: Arina Ielchiieva
• Created: 09/Jul/18 20:28
• Updated: 14/Jul/18 17:43
• Resolved: 14/Jul/18 17:43

Description

System table columns can contain null values but they are incorrectly marked as non-nullable as shown in example table below:  

0: jdbc:drill:drillbit=10.10.10.191> describe sys.boot;
+-------------------+--------------------+--------------+
|    COLUMN_NAME    |     DATA_TYPE      | IS_NULLABLE  |
+-------------------+--------------------+--------------+
| name              | CHARACTER VARYING  | NO           |
| kind              | CHARACTER VARYING  | NO           |
| accessibleScopes  | CHARACTER VARYING  | NO           |
| optionScope       | CHARACTER VARYING  | NO           |
| status            | CHARACTER VARYING  | NO           |
| num_val           | BIGINT             | NO           |
| string_val        | CHARACTER VARYING  | NO           |
| bool_val          | BOOLEAN            | NO           |
| float_val         | DOUBLE             | NO           |
+-------------------+--------------------+--------------+

 

Note that several columns are nulls: 

+---------------------------------------------------+----------+------------------+-------------+--------+---------+------------+----------+-----------+
|                       name                        |   kind   | accessibleScopes | optionScope | status | num_val | string_val | bool_val | float_val |
+---------------------------------------------------+----------+------------------+-------------+--------+---------+------------+----------+-----------+
drill.exec.options.exec.udf.enable_dynamic_support | BOOLEAN | BOOT | BOOT | BOOT | null | null | true | null |

 

Because of the not-null metadata, the predicates on these tables such as `WHERE <column> IS NULL` evaluate to FALSE which is incorrect. 

 

Issue Links

• links to: GitHub Pull Request #1371