Page History

...

Whether to rewrite count distinct into 2 stages, i.e., the first stage uses multiple reducers with the count distinct key and the second stage uses a single reducer without key.

hive.optimize.remove.sq_count_check

• Default Value: false

• Added In: Hive 3.0.0 with HIVE-16793

Whether to remove an extra join with sq_count_check UDF for scalar subqueries with constant group by keys. 

hive.multigroupby.singlemr

• Default Value: false
• Added In: Hive 0.8.0 with HIVE-2056
• Removed In: Hive 0.9.0 by HIVE-2621 (see hive.multigroupby.singlereducer)

...