When you optimize the order of dimensions in a cube, TM1 does not change the actual order of dimensions in the cube structure. TM1 does change the way dimensions are ordered internally on the server, but because the cube structure is not changed, any rules, functions, or applications referencing the cube remain valid.
As you change the order of dimensions, you can instantly view a report detailing the impact your changes have on cube memory consumption.
For the following reasons, you should optimize the order of dimensions in a cube only in a development environment while you are trying to determine optimal cube configuration:
Significant memory resources are required for the TM1 server to reconfigure the order of dimensions in a cube. During the re-ordering process, the temporary RAM on the TM1 server increases by a factor of two for the cube that you are re-ordering. For example, a 50 MB cube requires 100 MB of RAM to reconfigure.
Re-ordering puts a read lock on the server, locking all user requests while the re-order is performed.