[
https://issues.apache.org/jira/browse/HIVE-18350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16353199#comment-16353199
]
Sergey Shelukhin commented on HIVE-18350:
-----------------------------------------
Left some comments on RB
> load data should rename files consistent with insert statements
> ---------------------------------------------------------------
>
> Key: HIVE-18350
> URL: https://issues.apache.org/jira/browse/HIVE-18350
> Project: Hive
> Issue Type: Bug
> Reporter: Deepak Jaiswal
> Assignee: Deepak Jaiswal
> Priority: Major
> Attachments: HIVE-18350.1.patch, HIVE-18350.10.patch,
> HIVE-18350.11.patch, HIVE-18350.12.patch, HIVE-18350.13.patch,
> HIVE-18350.2.patch, HIVE-18350.3.patch, HIVE-18350.4.patch,
> HIVE-18350.5.patch, HIVE-18350.6.patch, HIVE-18350.7.patch,
> HIVE-18350.8.patch, HIVE-18350.9.patch
>
>
> Insert statements create files of format ending with 0000_0, 0001_0 etc.
> However, the load data uses the input file name. That results in inconsistent
> naming convention which makes SMB joins difficult in some scenarios and may
> cause trouble for other types of queries in future.
> We need consistent naming convention.
> For non-bucketed table, hive renames all the files regardless of how they
> were named by the user.
> For bucketed table, hive relies on user to name the files matching the
> bucket in non-strict mode. Hive assumes that the data belongs to same bucket
> in a file. In strict mode, loading bucketed table is disabled.
> This will likely affect most of the tests which load data which is pretty
> significant due to which it is further divided into two subtasks for smoother
> merge.
> For existing tables in customer database, it is recommended to reload
> bucketed tables otherwise if customer tries to run SMB join and there is a
> bucket for which there is no split, then there is a possibility of getting
> incorrect results. However, this is not a regression as it would happen even
> without the patch.
> With this patch however, and reloading data, the results should be correct.
> For non-bucketed tables and external tables, there is no difference in
> behavior and reloading data is not needed.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
