shared pool size ?

[Flyrc]

when i set shared_pool=72M in init.ora and start the instance, it comes real shared_pool size as 88M at OEM, and i think the difference is coming from:

- shared_pool_reserved_size
- create_bitmap_area_size
- bitmap_merge_area_size
- sort_area_size (inside UGA???)
- UGA size (v$sesstat join v$statname to query)
although i configure large pool, i know UGA still
takes memory of shared pool.

Am i right for the explaination ?

(DBS configuration: shared server config)

 

[Flyrc]

Continue above question:

If in 9i I set PGA_aggregate_target parameter, I can remove
create_bitmap_area_size & bitmap_merge_area_size setting and save SGA memory by allocating BITMAP index memory usage into PGA?