Mapjoin Usage Question

[hadoop n00b]

Hi,

How do I use the mapjoin hint in a query.

Say, I have two tables t1 and t2 where t2 is the smaller table. Do I specify
t2 in the mapjoin hint?

select /*+ mapjoin(b)*/ * from t1 join t2 b on (a.id = b.id)

If I am joining two smaller tables, can I specify two clauses in the
mapjoin? /*+mapjoin(b,c)*/?

I am unable to find much documentation on this. I am using CDH2 with Hive
0.4.1

Thanks!