[jira] [Commented] (HIVE-22062) WriteId is not updated for a partitioned ACID table when schema changes

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

    [ https://issues.apache.org/jira/browse/HIVE-22062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16985113#comment-16985113 ] 

Csaba Ringhofer commented on HIVE-22062:
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Linked HIVE-22565 as it also deals with changing table level writeId.

> WriteId is not updated for a partitioned ACID table when schema changes
> -----------------------------------------------------------------------
>
>                 Key: HIVE-22062
>                 URL: https://issues.apache.org/jira/browse/HIVE-22062
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Gabor Kaszab
>            Assignee: Laszlo Kovari
>            Priority: Major
>              Labels: ACID
>
> Changing the schema (e.g. adding a new column) of a non-partitioned ACID table results in the table-level writeId being incremented. This is as expected.
> However, if you do the same on a partitioned ACID table then neither the table-level nor the partition-level writeIds are updated. I would expect in this case to increment the table-level writeId to reflect that the table has been changed.
> Note, that get_valid_write_ids() shows that the high watermark is incremented even though the writeId isn't.
> Update: I'd extend the scope of this Jira further a bit. There are a number of use cases in Hive that doesn't result in a writeId change on ACID tables and as a result there is no way from other systems (like Impala) to judge if a refresh should be run on a table or not. The only option is to every time update all the data for a table that is expensive. E.g. Additionally to the above use-case compaction is something that is not noticeable outside from Hive.



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