[jira] [Work started] (HIVE-25293) Alter partitioned table with "cascade" option create too many columns records.

["yongtaoliao (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-25293?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Work on HIVE-25293 started by yongtaoliao.
------------------------------------------
> Alter partitioned table with "cascade" option create too many columns records.
> ------------------------------------------------------------------------------
>
>                 Key: HIVE-25293
>                 URL: https://issues.apache.org/jira/browse/HIVE-25293
>             Project: Hive
>          Issue Type: Improvement
>          Components: Metastore
>    Affects Versions: 2.3.3, 3.1.2
>            Reporter: yongtaoliao
>            Assignee: yongtaoliao
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> When alter partitioned table with "cascade" option, all partitions supports to be updated. Currently, a CD_ID will be created for each partition, associated with a set of Columns, which will cause a large amount of redundant data in the metadata database.
> The following DDL statements can reproduce this scenario：
>  
> {code:java}
> create table test_table (f1 int) partitioned by (p string);
> alter table test_table add partition(p='a');
> alter table test_table add partition(p='b');
> alter table test_table add partition(p='c');
> alter table test_table add columns (f2 int) cascade;{code}
> All partitions use the table's `CD_ID` before adding columns, while each partition use their own `CD_ID` after adding columns.
>  
> My proposal is all partitions should use the same `CD_ID` when table was altered with "cascade" option.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)