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https://issues.apache.org/jira/browse/HIVE-4175?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Xiang Zhang updated HIVE-4175:
------------------------------
    Description: 
* My deserializer is expecting to receive one of 2 different subclasses of 
Writable, but in certain circumstances it receives an empty instance of 
org.apache.hadoop.io.Text. This only happens for task attempts where I observe 
the file called "emptyFile" in the list of input splits.

I'm doing queries over an external year/month/day partitioned table that have 
eagerly created partitions for, so as of today for example, I may do a query 
where year = 2013 and month = 3 which includes empty partitions.

In the course of investigation I downloaded the sequence files to confirm they 
were ok. Once I realized that processing of empty partitions was to blame, I am 
able to work around the issue by bounding my queries to populated partitions.

Can the need for the emptyFile be eliminated in the case where there's already 
a bunch of splits being processed? Failing that, can the mapper detect the 
current input is from emptyFile and not call the deserializer.

  was:
My deserializer is expecting to receive one of 2 different subclasses of 
Writable, but in certain circumstances it receives an empty instance of 
org.apache.hadoop.io.Text. This only happens for task attempts where I observe 
the file called "emptyFile" in the list of input splits. 

I'm doing queries over an external year/month/day partitioned table that have 
eagerly created partitions for, so as of today for example, I may do a query 
where year = 2013 and month = 3 which includes empty partitions.

In the course of investigation I downloaded the sequence files to confirm they 
were ok. Once I realized that processing of empty partitions was to blame, I am 
able to work around the issue by bounding my queries to populated partitions.

Can the need for the emptyFile be eliminated in the case where there's already 
a bunch of splits being processed? Failing that, can the mapper detect the 
current input is from emptyFile and not call the deserializer.



> Injection of emptyFile into input splits for empty partitions causes 
> Deserializer to fail
> -----------------------------------------------------------------------------------------
>
>                 Key: HIVE-4175
>                 URL: https://issues.apache.org/jira/browse/HIVE-4175
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 0.10.0
>         Environment: CDH4.2, using MR1
>            Reporter: James Kebinger
>            Priority: Minor
>
> * My deserializer is expecting to receive one of 2 different subclasses of 
> Writable, but in certain circumstances it receives an empty instance of 
> org.apache.hadoop.io.Text. This only happens for task attempts where I 
> observe the file called "emptyFile" in the list of input splits.
> I'm doing queries over an external year/month/day partitioned table that have 
> eagerly created partitions for, so as of today for example, I may do a query 
> where year = 2013 and month = 3 which includes empty partitions.
> In the course of investigation I downloaded the sequence files to confirm 
> they were ok. Once I realized that processing of empty partitions was to 
> blame, I am able to work around the issue by bounding my queries to populated 
> partitions.
> Can the need for the emptyFile be eliminated in the case where there's 
> already a bunch of splits being processed? Failing that, can the mapper 
> detect the current input is from emptyFile and not call the deserializer.



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