Alter SGA

SQL> Alter system set sga_max_size=3072M scope=spfile;

System altered.

SQL> shu immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 1795162112 bytes
Fixed Size 2021504 bytes
Variable Size 1124075392 bytes
Database Buffers 654311424 bytes
Redo Buffers 14753792 bytes
Database mounted.
Database opened.
SQL>
SQL> show parameter sga_max_size;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sga_max_size big integer 1712M
SQL>
SQL>
SQL>
SQL> show parameter sga

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1712M
sga_target big integer 880M
SQL>
SQL>

SQL> alter system set sga_target=3050M scope=both;

System altered.

SQL> shu immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 1795162112 bytes
Fixed Size 2021504 bytes
Variable Size 301991808 bytes
Database Buffers 1476395008 bytes
Redo Buffers 14753792 bytes
Database mounted.
Database opened.
SQL> show parameter sga

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1712M
sga_target big integer 1664M
SQL>