Can I get this issue assigned to me? I have a basic implementation working, which I'd like to contribute.
It wraps the DBInputFormat and DBOutputFormat classes.
It expects values for the DBConfiguration properties to be provided through the SERDEPROPERTIES block in the create table statement. The configureTableJobProperties() method copies these properties out of the table description and into each job context.
It also allows users to set SerDe properties which will cause the DBOutputFormat to generate UPSERT sql statements or DELETE sql statements instead of the vanilla INSERT sql generated by default. Right now this feature has a MySql bias. I am still trying to decide what the best way is to make this more database vendor agnostic.