[HIVE-26105] Show columns shows extra values if column comments contains specific Chinese character

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: Hive, HiveServer2
• Labels: pull-request-available
• Assignee: mahesh kumar behera
• Reporter: mahesh kumar behera
• Created: 01/Apr/22 04:14
• Updated: 05/Apr/22 08:19
• Resolved: 05/Apr/22 08:19

Description

The issue is happening because the UTF code for one of the Chinese character contains the binary value of '\r' (CR). Because of this, the Hadoop line reader (used by fetch task in Hive) is assuming the value after that character as new value and this extra value with junk is getting displayed. The issue is with 0x540D 名 ... The last value is "D" ..that is 13. While reading the result, Hadoop line reader interpreting it as CR ( '\r'). Thus an extra value with Junk is coming as output. For show column, we do not need the comments. So while writing to the file, only column names should be included.

https://github.com/apache/hadoop/blob/0fbd96a2449ec49f840d93e1c7d290c5218ef4ea/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/LineReader.java#L238

 

create table tbl_test  (fld0 string COMMENT  '期 ' , fld string COMMENT '期末日期', fld1 string COMMENT '班次名称', fld2  string COMMENT '排班人数');

show columns from tbl_test;
+--------+
| field  |
+--------+
| fld    |
| fld0   |
| fld1   |
| �      |
| fld2   |
+--------+
5 rows selected (171.809 seconds)
 

Issue Links

• links to: GitHub Pull Request #3166