hadoop should provide a common way to wrap instances with different types into 
one type
---------------------------------------------------------------------------------------

                 Key: HADOOP-689
                 URL: http://issues.apache.org/jira/browse/HADOOP-689
             Project: Hadoop
          Issue Type: Improvement
          Components: io
         Environment: All environment
            Reporter: Feng Jiang


When two sequence files, which have same Key type but different Value types, 
are mapped out to reduce, multiple Value types is not allowed. In this case, we 
need a way to wrap instances with different types into one class type to reduce.

In current code, ObjectWritable is a sole choice. but it costs too many space, 
because the class declaration will be appended into output file as a string for 
every Key-value pair.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: 
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Reply via email to