Oracle® Database 11g / 12c / 18c error codes ORA-00839: SGA_TARGET cannot be modified to the specified value

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

Oracle Error Code: ORA-00839

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

Action: 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.