Oracle Database Discussions

Hi Guys,

I understand that

LIO = logical = buffer cache. LIO may have incurred a PIO in order to get into the cache in the first place.

PIO = physical = disk read

I understand that physical i/o will read from disk causing increase in disk i/o and result in long elapsed time.

My question here is whether pure LIOs (data detected in cache, read from memory) or physical IOs will consume more cpu?

I'm just curious whether an increase of cpu high ulization is due to high number of physical i/o perhaps due to shortage of ram allocated to the db or actually more towards the high number of pure LIOs (memory is sufficient to cache the data, very less PIO).

thanks