Changing Physical Schema

In addition to your initial superprojections, you can create new projections using the CREATE PROJECTION command. A single table can have multiple projections, if necessary.

If you want to replace a superprojection, a new superprojection must be created before the old one is removed.


  1. Review the existing projections in your Data Warehouse instance:

    SELECT * FROM projections p WHERE p.projection_schema = '[DW_ID]'
  2. Run the CREATE PROJECTION commands to create new projections. The projection is automatically populated with data after creation.

  3. Drop projections that are no longer necessary using the DROP PROJECTION command.


Occasionally, the following error may occur when dropping a projection:

ROLLBACK: Projection cannot be dropped because history after AHM would be lost

In this case, try again later. If the problem persists, contact GoodData Customer Support.