[
https://issues.apache.org/jira/browse/HIVE-23354?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17105863#comment-17105863
]
John Sherman commented on HIVE-23354:
-------------------------------------
I've adjusted the patch to check for speculative execution and throw an
exception. After discussion with other Hive contributors/committers, MR is not
as widely used with newer version of Hive and speculative execution with Tez
seems to be marked as unstable. Especially since this code as it currently
exists is also broken for speculative execution. A follow up Jira will be made
once this patch gets reviewed to look into supporting speculative execution in
this path.
> Remove file size sanity checking from compareTempOrDuplicateFiles
> -----------------------------------------------------------------
>
> Key: HIVE-23354
> URL: https://issues.apache.org/jira/browse/HIVE-23354
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Reporter: John Sherman
> Assignee: John Sherman
> Priority: Major
> Attachments: HIVE-23354.1.patch, HIVE-23354.2.patch
>
>
> [https://github.com/apache/hive/blob/cdd55aa319a3440963a886ebfff11cd2a240781d/ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java#L1952-L2010]
> compareTempOrDuplicateFiles uses a combination of attemptId and fileSize to
> determine which file(s) to keep.
> I've seen instances where this function throws an exception due to the fact
> that the newer attemptId file size is less than the older attemptId (thus
> failing the query).
> I think this assumption is faulty, due to various factors such as file
> compression and the order in which values are written. It may be prudent to
> trust that the newest attemptId is in fact the best choice.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
