Details
Major Description
This is idea that was recently brought to my attention. The use case is a user wants to essentially clone a subset of a table into an existing table. Currently cloning does not allow this. Current option is to copy the files in hdfs and then bulk import, since bulk import moves the files. This is pretty wasteful. Under the hood, the system can handle the cross-linking between files like that. We just need a mechanism to provide the ability to assign a subset of data to another region.
Potential uses include the above mentioned, as well as the potential for users to bring fresh data into a table which was cloned and modified. There may be other cases, but I haven't fully thought out this problem space.
The biggest problem with this is it does put the onus on the user for ensuring that data in the in memory maps is flushed before moving, as well as for handling the possibility of duplicate data.