Just a proof of concept for: Large implementations need a viable upgrade path to 1.9.x - TRUNK-4117

https://tickets.openmrs.org/browse/TRUNK-4117

This is not a fix. It is just trying to see if applying the change sets to empty obs and encounter tables, and then copying the data into them, can improve the performance. I have tested this on Mathew's (Masaka site in Uganda) 6.72 GB database and it took 35 minutes to complete the upgrade from version 1.8.4 to version 1.11
He told me that it took him more than a week to do an upgrade which did not complete and then he aborted it.

This database has:
patients          =         21,604
encounters     =       441,944
observations  =   10,576,185