HIVE-3976, the maximum precision is set to 65, and maximum scale is to 30. After discussing with several folks in the community, it's determined that 38 as a maximum for both precision and scale are probably sufficient, in addition to the potential performance boost that might become possible to some implementation.
This task is to make such a change. The change is expected to be trivial, but it may impact many test cases. The reason for a separate JIRA is that patch in
HIVE-3976 is already in a good shape. Rather than destabilizing a bigger patch, a dedicate patch will facilitates both reviews.
The wiki document will be updated shortly.