To avoid hitting web-facing database servers with long running queries, ChangeDispatcher should use a configurable DB server group. To do this, we need to:
- move ConsistentReadConnectionManager to lib (or to core)
- allow the DB server group(s) to be set in ConsistentReadConnectionManager's constructor
- make EntityChangeLookup and SqlChangeDispatchCoordinator use ConsistentReadConnectionManager
- allow the DB server group to use for the ConsistentReadConnectionManager used by ChangeDispatcher to be defined from the command line.
- add a command line argument to dispatchChanges.php for specifying the DB server group.
The same should probably be done for DumpGenerator.