[
https://issues.apache.org/jira/browse/HIVE-5996?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13847579#comment-13847579
]
Xuefu Zhang commented on HIVE-5996:
-----------------------------------
Yes, in theory, but unlikely. Current precision formula, 10 + p as the output
precision, gives some room. Of course, if the input precision is already at
maximum, then output type precision will the same as the input precision. In
that case, for really big numbers, it can overflow. Anyway, I'm going to close
the JIRA, so the discussion.
> Query for sum of a long column of a table with only two rows produces wrong
> result
> ----------------------------------------------------------------------------------
>
> Key: HIVE-5996
> URL: https://issues.apache.org/jira/browse/HIVE-5996
> Project: Hive
> Issue Type: Bug
> Components: UDF
> Affects Versions: 0.12.0
> Reporter: Xuefu Zhang
> Assignee: Xuefu Zhang
> Attachments: HIVE-5996.patch
>
>
> {code}
> hive> desc test2;
> OK
> l bigint None
> hive> select * from test2;
> OK
> 6666666666666666666
> 5555555555555555555
> hive> select sum(l) from test2;
> OK
> -6224521851487329395
> {code}
> It's believed that a wrap-around error occurred. It's surprising that it
> happens only with two rows. Same query in MySQL returns:
> {code}
> mysql> select sum(l) from test;
> +----------------------+
> | sum(l) |
> +----------------------+
> | 12222222222222222221 |
> +----------------------+
> 1 row in set (0.00 sec)
> {code}
> Hive should accommodate large number of rows. Overflowing with only two rows
> is very unusable.
--
This message was sent by Atlassian JIRA
(v6.1.4#6159)
