Today I decided to increase memory but before that I wanted to change sga_max_size`s value. Because in my production database configured sga_max_size to 12Gb. It means independing on busy or idle of instance state, SGA could not be more than 12GB (it is worse). The SGA_MAX_SIZE specifies the maximum size of the SGA for the lifetime of the instance. Our instance configured AMM: select name, value from v$parameter where name like 'memory%' memory_target 32212254720 memory_max_target 32212254720 --Checking init file -bash-3.2$ more initPROD.ora| grep -i sga PROD.__sga_target=12616466432 *.sga_max_size=25769803776 *.sga_target=0 -bash-3.2$ SGA_MAX_SIZE is not dynamic value, after changing those value, you should restart instance. SQL> show parameter sga NAME TYPE VALUE ------------------...