Hi,

I am trying to understand the algorithm used by Oracle when using pga_aggregate target and it looks like to get the information on Expected_WorkAreaSize, Oracle already knows about the value of optimal_size(cache size) and onepass_size so I was wondering how oracle calculate this values. Also in the same white paper it is mentioned that to sort the 10GB of input data Oracle only needs about 40MB for 1 pass but I thought to sort 10gb using 40MB bucket we need lot of passes so how it calcuate this 40MB for onepass.

Thanks

--Harvinder