...
No Format |
---|
set hive.auto.convert.join=true; select count(*) from store_sales join time_dim on (ss_sold_time_sk = t_time_sk) |
The default value for hive.auto.convert.join was false in Hive 0.10.0. Hive 0.11.0 changed the default to true (HIVE-3297).
MAPJOINs are processed by loading the smaller table into an in-memory hash map and matching keys with the larger table as they are streamed through. The prior implementation has this division of labor:
...