We've just made changes to increase memory and implement hugepages. One of the objectives was to also increase db_cache_size to 26G, but got an error saying there was not enough memory. We have 64G memory with 42G in sga and 7G in pga. in our parameter file i have both sga_max and sga_target. I see someone that got the same error resolved the problem by setting sga_target =0 then alter system set db_cache_size to desired size.
My question is since the application is up, what's the impact of setting sga_target to 0 while there are users on the system?