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https://issues.apache.org/jira/browse/HIVE-6016?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sushanth Sowmyan updated HIVE-6016:
-----------------------------------

    Description: 
Prashant and I discovered that the implementation of the wrapping Iterator in 
listLocatedStatus at 
https://github.com/apache/hive/blob/2d2f89c21618341987c1257a88691981f1f606c7/shims/src/0.23/java/org/apache/hadoop/hive/shims/Hadoop23Shims.java#L350-L393
 is broken.

Basically, if you had files (a,b,_s) , with a filter that is supposed to filter 
out _s, we expect an output result of (a,b). Instead, we get (a,b,null), with 
hasNext looking at the next value to see if it's null, and using that to decide 
if it has any more entries, and thus, (a,b,_s) becomes (a,b).

There's a boundary condition on the very first pick, which causes a (_s,a,b) to 
result in (_s,a,b), bypassing the filter, and thus, we wind up with a resultant 
unfiltered (_s,a,b) which orc breaks on.

The effect of this bug is that Orc will not be able to read directories where 
there is a _SUCCESS file, say, as the first entry returned by the FileStatus.


  was:
Prashant and I discovered that the implementation of the wrapping Iterator in 
listLocatedStatus at 
https://github.com/apache/hive/blob/2d2f89c21618341987c1257a88691981f1f606c7/shims/src/0.23/java/org/apache/hadoop/hive/shims/Hadoop23Shims.java#L350-L393
 is broken.

Basically, if you had files (a,b,_s) , with a filter that is supposed to filter 
out _s, we expect an output result of (a,b). Instead, we get (a,b,null), with 
hasNext looking at the next value to see if it's null, and using that to decide 
if it has any more entries, and thus, (a,b,_s) becomes (a,b).

There's a boundary condition on the very first pick, which causes a (_s,a,b) to 
result in (_s,a,b), bypassing the filter, and thus, we wind up with a resultant 
unfiltered (_s,a,b) which orc breaks on.



> Hadoop23Shims has a bug in listLocatedStatus impl.
> --------------------------------------------------
>
>                 Key: HIVE-6016
>                 URL: https://issues.apache.org/jira/browse/HIVE-6016
>             Project: Hive
>          Issue Type: Bug
>          Components: Shims
>    Affects Versions: 0.13.0
>            Reporter: Sushanth Sowmyan
>            Assignee: Prasanth J
>         Attachments: HIVE-6016.1.patch
>
>
> Prashant and I discovered that the implementation of the wrapping Iterator in 
> listLocatedStatus at 
> https://github.com/apache/hive/blob/2d2f89c21618341987c1257a88691981f1f606c7/shims/src/0.23/java/org/apache/hadoop/hive/shims/Hadoop23Shims.java#L350-L393
>  is broken.
> Basically, if you had files (a,b,_s) , with a filter that is supposed to 
> filter out _s, we expect an output result of (a,b). Instead, we get 
> (a,b,null), with hasNext looking at the next value to see if it's null, and 
> using that to decide if it has any more entries, and thus, (a,b,_s) becomes 
> (a,b).
> There's a boundary condition on the very first pick, which causes a (_s,a,b) 
> to result in (_s,a,b), bypassing the filter, and thus, we wind up with a 
> resultant unfiltered (_s,a,b) which orc breaks on.
> The effect of this bug is that Orc will not be able to read directories where 
> there is a _SUCCESS file, say, as the first entry returned by the FileStatus.



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