Updating DB_CACHE_SIZE With Alter System Scope=SPFILE Fails with ORA-384

Updating DB_CACHE_SIZE With Alter System Scope=SPFILE Fails with ORA-384

SQL> alter system set db_cache_size=<new value> scope=spfile;
ORA-384 Insufficient memory to grow cache 

The problem stems from having SGA_TARGET set to a non-zero value.

You need to unset SGA_TARGET, restart your database and modify DB_CACHE_SIZE, and then reset SGA_TARGET as before.

SQL> alter system set sga_target=0 scope=spfile;
SQL> shutdown immediate;
SQL> startup
SQL> alter system set db_cache_size=<new value> scope=spfile;
SQL> alter system set sga_target=<old value> scope=spfile;
SQL> shutdown immediate;
SQL> startup


Cheers !!!!!!!!!!!!!!!!!!

>>>> Before Implementing anything in PROD test properly in atleast 2 test instances to validate the solution.