Using the same InputFormat class for JOIN?

[yan qi]

Hi,

  I have a question about the JOIN operation in Hive.

  For example, I have a query, like

   select tmp7.* from tmp7 join tmp2 on (tmp7.c2 = tmp2.c1);

  Clearly, there is a JOIN involved in the statement.
   1. tmp2 and tmp7 are two tables.
    2. c2 and c1 are columns belonging to tmp7 and tmp2 respectively.

  I found that this query is executed in Hive with a MapReduce Job.
Therefore, I am wondering if tmp2 and tmp7 are both assumed to share the
same InputFormat class.

  What if tmp2 and tmp7 are using different InputFormat classes to read
records?


Thanks,

WS