1. Review the current and PGA_AGGREGATE_TARGET SGA_TARGET parameters.
SYS@oradb> show parameter target;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target integer 0
db_flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 0
memory_target big integer 0
parallel_servers_target integer 256
pga_aggregate_target big integer 2951M
sga_target big integer 4G
2. modify the relevant parameters, the parameter to 0 sga and pga
alter system set memory_max_target=16384m scope=spfile;
alter system set memory_target=16384m scope=spfile;
alter system set sga_target=0 scope=spfile;
alter system set sga_max_size=0 scope=spfile;
alter system set pga_aggregate_target=0 scope=spfile;
3. Restart the database instance:
SQL>shutdown immediate;
SQL>startup;
SYS@oradb> show parameter target;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target integer 0
db_flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 16G
memory_target big integer 16G
parallel_servers_target integer 256
pga_aggregate_target big integer 0
sga_target big integer 0
4. Monitor and optimize memory AMM
V $ MEMORY_DYNAMIC_COMPONENTS dynamic performance views to display the current dynamic memory size of all the components.
Dynamic performance view V $ MEMORY_RESIZE_OPS have a circular history buffer, view recent 16G memory requests circumstances.
Dynamic performance view V $ MEMORY_TARGET_ADVICE, and give a memory optimization suggestions.
SYS@oradb> SELECT * FROM v$memory_target_advice ORDER BY memory_size;
MEMORY_SIZE MEMORY_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR VERSION
----------- ------------------ ------------ ------------------- ----------
4096 .25 487 1 0
8192 .5 487 1 0
10240 .625 487 1 0
12288 .75 487 1 0
14336 .875 487 1 0
16384 1 487 1 0
18432 1.125 487 1 0
20480 1.25 487 1 0
22528 1.375 487 1 0
24576 1.5 487 1 0
26624 1.625 487 1 0
28672 1.75 487 1 0
30720 1.875 487 1 0
32768 2 487 1 0
备注:Automatic Shared Memory Management (ASMM) was introduced in 10g. You enable the automatic shared memory management feature by setting the SGA_TARGET parameter to a non-zero value.
About SGA_TARGET dynamic view of memory is recommended as follows:
SYS@oradb> select * from v$sga_target_advice;
SGA_SIZE SGA_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR ESTD_PHYSICAL_READS
---------- --------------- ------------ ------------------- -------------------
2457 .25 488 1 42221
3685 .3749 488 1 42221
4914 .5 488 1 42221
6142 .6249 488 1 42221
7371 .75 488 1 42221
8599 .8749 488 1 42221
9828 1 488 1 42221
11056 1.1249 488 1 42221
12285 1.25 488 1 42221
13513 1.3749 488 1 42221
14742 1.5 488 1 42221
15970 1.6249 488 1 42221
17199 1.75 488 1 42221
18427 1.8749 488 1 42221
19656 2 488 1 42221