Hi Souvik In earlier versions of hive you had to give the map join hint. But in later versions just set hive.auto.convert.join = true; Hive automatically selects the smaller table. It is better to give the smaller table as the first one in join.
You can use a map join if you are joining a small table with a large one, in terms of data size. By small, better to have the smaller table size in range of MBs. Regards Bejoy KS Sent from remote device, Please excuse typos -----Original Message----- From: Souvik Banerjee <souvikbaner...@gmail.com> Date: Fri, 7 Dec 2012 13:58:25 To: <user@hive.apache.org> Reply-To: user@hive.apache.org Subject: Map side join Hello everybody, I have got a question. I didn't came across any post which says somethign about this. I have got two tables. Lets say A and B. I want to join A & B in HIVE. I am currently using HIVE 0.9 version. The join would be on few columns. like on (A.id1 = B.id1) AND (A.id2 = B.id2) AND (A.id3 = B.id3) Can I ask HIVE to use map side join in this scenario? Should I give a hint to HIVE by saying /*+mapjoin(B)*/ Get back to me if you want any more information in this regard. Thanks and regards, Souvik.
