Slow dimension because it had a default member

问题

I have an SSAS cube that has a dimension with about 500,000 members. Performance is surprisingly good until I had a default member on one of the attributes (a boolean Yes/No value that we default to Yes).

This change makes a refresh go from 5 seconds to over 20 minutes.

Are default values known to be bad for performance? I can't really see anything on Google suggesting that they are bad performers.

For context, when refreshing a PivotTable, Excel was executing a heap of WITH MEMBER statements, with each taking about 3.5 seconds. Removing the default member brought that down to 40ms.

来源：https://stackoverflow.com/questions/39739236/slow-dimension-because-it-had-a-default-member