Oracle Solution for Error ora-00839

ORA-00839: SGA_TARGET cannot be modified to the specified value

What triggered the Error:

The specified value of SGA_TARGET was not compatible with current settings of PGA_AGGREGATE_TARGET and MEMORY_TARGET/MEMORY_MAX_TARGET.

What should we do to fix it:

Set SGA_TARGET to be no more than the difference of MEMORY_TARGET/MEMORY_MAX_TARGET and PGA_AGGREGATE_TARGET. Also ensure that the current PGA memory used for non-auto workareas is low.