When the locially dropped column is also physically dropped

["rupesh bajaj" <rupesh.bajaj@xxxxxxxxx>]

Hi,
I have dropped a column (say column name is 'A') from the relation R. By setting the attisdropped as true in the pg_catalog.pg_attribute table. But the column is dropped locially not the physically. Can you please tell me when this column will be physically also dropped. Is this column is automatically physically dropped? or I have to run some command to dropped it physically.

Thanks,
Rupesh Bajaj