pga requirement as per high watermark

select

(select highwater from dba_high_water_mark_statistics where name = ('SESSIONS'))*(2048576+a.value+b.value)/1024/1024 pga_size_MB

from

v$parameter a,

v$parameter b

where

a.name = 'sort_area_size'

and

b.name = 'hash_area_size'

;