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From "Chris Drome (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-13756) Map failure attempts to delete reducer _temporary directory on multi-query pig query
Date Fri, 13 May 2016 09:21:12 GMT
Chris Drome created HIVE-13756:
----------------------------------

             Summary: Map failure attempts to delete reducer _temporary directory on multi-query
pig query
                 Key: HIVE-13756
                 URL: https://issues.apache.org/jira/browse/HIVE-13756
             Project: Hive
          Issue Type: Bug
          Components: HCatalog
    Affects Versions: 2.0.0, 1.2.1
            Reporter: Chris Drome
            Assignee: Chris Drome


A pig script, executed with multi-query enabled, that reads the source data and writes it
as-is into TABLE_A as well as performing a group-by operation on the data which is written
into TABLE_B can produce erroneous results if any map fails. This results in a single MR job
that writes the map output to a scratch directory relative to TABLE_A and the reducer output
to a scratch directory relative to TABLE_B.

If one or more maps fail it will delete the attempt data relative to TABLE_A, but it also
deletes the _temporary directory relative to TABLE_B. This has the unintended side-effect
of preventing subsequent maps from committing their data. This means that any maps which successfully
completed before the first map failure will have its data committed as expected, other maps
not, resulting in an incomplete result set.



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