org.apache.tajo.master includes a mixed of classes for TajoMaster and QueryMaster. It looks somewhat messy. This patch refactors them to be located in a proper package. Especially, I did as follows:
- Move some classes to org.apache.tajo.querymaster
- Move org.apache.tajo.scheduler to org.apache.tajo.master.scheduler
- Move some classes in org.apache.tajo.master to tajo.apache.tajo.master.exec
- Move some classes in org.apache.tajo.master to org.apache.tajo.ha.
- Remove FragmentPair, ScheduledFetch, and QueryMasterRunner which are unused.
- Move Abstract/Default TaskScheduler and TaskScheduler* to org.apache.tajo.querymaster.
This is just a move issue of classes. Now, nobody seems to be working on these packages. So, I think that now is the change to refactor them.