PM_ORDER_DATA_READ running too long

I'm using the FM - PM_ORDER_DATA_READ to extract workorder data for divestiture. But the program execution time is running over few days due to the

LOOP AT icaufv-aufnr.

Another thing I have noticed - Unless the FM is run as a backgroud job for large data, SAP errors 'out of memory'.

Can anyone suggest how to extract all workorder info and quicken the execution time?

Thanks

G