Using maxl Clearing particular region of data taking more time than original data load

I Have a maxl script which basically peforms below operations:

1.Clear the specific region of data

2.Loads data into cube with buffer id

Maxl statement for Clear region:

alter database cubename .dbname clear data in region 'Crossjoin({([Scenario])},{Descendants(Member)})' physical;

The above statement is executing almost 50mins in production environment, whereas it is comparatively higher than our original full data load.

Please advise why the clear region statement alone taking much time??Thanks in advance!!!

Regards,

Lakshmi.