Symptoms When trying to set SGA_TARGET using an ALTER SYSTEM command, the following errors are raised: ORA-00843: Parameter not taking MEMORY_MAX_TARGET into account ORA-00849: SGA_TARGET 10737418240 cannot be set to more than MEMORY_MAX_TARGET 0. Changes MEMORY_MAX_TARGET was set to 0. Cause The problem is caused by the MEMORY_MAX_TARGET parameter explicitly being set to 0. In case AMM should not be used, MEMORY_MAX_TARGET should not be set at all. Solution解决方法： The solutions to the problem are: 1.create a PFILE from the SPFILE being used and remove the MEMORY_MAX_TARGET=0 and MEMORY_TARGET=0 lines. After that, use the modified PFILE to create a new SPFILE and start the instance with this new setup. 2.should the instance be running, then use the following commands to remove the explicit setting of MEMORY_TARGET=0 and MEMORY_MAX_TARGET=0: alter system reset memory_target; alter system reset memory_max_target;