From mailing list:
--Amazon Elastic MapReduce version of Hive seems to have a nice feature called "Variables." Basically you can define a variable via command-line while invoking hive with -d DT=2009-12-09 and then refer to the variable via $
within the hive queries. This could be extremely useful. I can't seem to find this feature even on trunk. Is this feature currently anywhere in the roadmap?--
This could be implemented in many places.
A simple place to put this is
in Driver.compile or Driver.run we can do string substitutions at that level, and further downstream need not be effected.
There could be some benefits to doing this further downstream, parser,plan. but based on the simple needs we may not need to overthink this.
I will get started on implementing in compile unless someone wants to discuss this more.