You can only specify one table, and make sure to include its name, i.e. /*+ mapjoin(t2)*/. For more info see http://wiki.apache.org/hadoop/Hive/JoinOptimization and http://www.slideshare.net/aiolos127/join-optimization-in-hive.
Also, you are using a relatively old version of Hive, but I'll let more experienced people on this list decide whether that's a problem :) On Thu, Jan 20, 2011 at 2:00 AM, hadoop n00b <new2h...@gmail.com> wrote: > 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!
