process - ssas attribute key cannot be found even though it exists and is not due to duplicates

Question

I was trying to rebuild my cube after making some changes the other day to the table/column names in the fact and dimension tables.

The process cube action kept returning the following error message:

The attribute key cannot be found when processing: Table: 'MyFactTableName', Column: 'MyDimensionKey', Value: 'SomeValue'. The attribute is 'MyDimensionKey'.

The other answers to similar questions referred to attributes with duplicate values, and cases where the attribute value was null in the or missing in either the Dimension or the Fact table.

Example related posts are:

• ssas dimension processing key not found error
• key not found error

There were no duplicate values in my case and the attribute value was not missing from either the Fact or Dimension table.

Thankfully the information in this post here solved my problem.

The suggestion was to process the affected Dimension by itself, and then process the affected measure group.

Any idea why this happens, how I could reproduce this? I'd like to know so that I can avoid it next time or so that it doesn't pop up again at a bad time while deploying an upgrade to the production environment.

Thanks in advance for your help.

EDIT: I'm using SSAS-2008, and the error occurred while trying to process the cube from within BIDS-2008.

Answer 1

This happens because your measure group is processed before the related dimensions. SSAS comes across a foreign key that's used to relate to a cube dimension, but the key is not known to the dimension itself.