sqoop-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jarek Jarcec Cecho (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SQOOP-489) Cannot define partition keys for Hive tables created through Sqoop
Date Fri, 25 May 2012 06:48:22 GMT

    [ https://issues.apache.org/jira/browse/SQOOP-489?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13283168#comment-13283168
] 

Jarek Jarcec Cecho commented on SQOOP-489:
------------------------------------------

I wasn't checking sources so I might be wrong here. But let me explain what I was afraid of
on example:

Imagine table with three columns A, B, C with one row - 1, 2, 3. User specify that A should
be used as partitioned column. Then after applying suggested fix we will create following
create table statement:

CREATE TABLE IF NOT EXISTS `FOO` (`B` STRING, `C` STRING) PARTITIONED BY (A STRING)

But sqoop import will by default import all columns and thus resulting in file "1, 2, 3".
Now when hive will read the file column B will contain value 1 (e.g. value of A), column C
will contain value 2 (value of column B) and value 3 for column C will be missing entirely
from hive perspective. Again I did no research nor try it in practice. It's solely based on
my experience and I wanted to express my worries prior any coding. 

Is it more clear now?

Jarcec
                
> Cannot define partition keys for Hive tables created through Sqoop
> ------------------------------------------------------------------
>
>                 Key: SQOOP-489
>                 URL: https://issues.apache.org/jira/browse/SQOOP-489
>             Project: Sqoop
>          Issue Type: Bug
>    Affects Versions: 1.4.1-incubating
>            Reporter: Kathleen Ting
>         Attachments: SQOOP-489.patch
>
>
> By enabling the table option, Sqoop includes every column in the table in the create
table query, and by enabling the hive-partition-key option, Sqoop blindly appends the "partitioned
by" clause. Now if you specify one of columns in the table in the hive-partition-key, this
will cause a syntax error in Hive.
> For example, if we have a table 'FOO' that has columns 'I' and 'J':
> sqoop create-hive-table --table FOO ...
> will generate the following Hive query:
> CREATE TABLE IF NOT EXISTS `FOO` ( `I` STRING, `J` STRING)
> Now if we add "--hive-partition-key I" to the command, Sqoop generates the following
query:
> CREATE TABLE IF NOT EXISTS `FOO` ( `I` STRING, `J` STRING) PARTITIONED BY (I STRING)
> The problem is that since 'I' is defined twice (once in CRATE TABLE and once in PARTITIONED
BY), this is a syntax error in Hive.
> This correct query would be something like:
> CREATE TABLE IF NOT EXISTS `FOO` (`J` STRING) PARTITIONED BY (I STRING)

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message