Hive Map join : out of memory Exception

set hive.auto.convert.join = false; it will not give u memory exception.

Processing rows: 300000 Hashtable size: 299999 Memory usage: 643070664 rate:0.604

At 300k rows the HT already uses 60% of your heap. First question to ask: are you sure you got the table order right, is the small table in the join really the smaller table in your data? When writing the query, the large table should be the last in the JOIN clause. Which Hive version are you on 0.9 or 0.11?

If you are on Hive 0.11 and you are specifying the join correctly then the first thing to try would be to increase the Heap size. From the above data (300k row ~> 650Mb Heap) you can figure out how much heap you need.

I faced this problem and was only able to get over it by using set hive.auto.convert.join=false