背景: 根据需求生产环境为了增加稳定性,避免内存组件过度扩张,因此使用ASMM自动共享内存管理方式,并且手工设定 shared_pool_size,db_cache_size的大小。 如下操作的原因是因为:在直接修改操作的时候报错: 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.
--1.查看当前内存组件参数值 col name for a30; col VALUE for a30; select INST_ID,name, VALUE / 1024 / 1024 size_MB, issys_modifiable from gv$parameter where name in ('pga_aggregate_target', 'memory_target', 'memory_max_target', 'sga_max_size', 'sga_target', 'shared_pool_size', 'db_cache_size', 'java_pool_size', 'large_pool_size', 'streams_pool_size') order by 2,1; --2.查看PGA使用过的最大值 select INST_ID,value/1024/1024 SIZE_M from gv$pgastat where name='maximum PGA allocated'; INST_ID SIZE_M ---------- ---------- 1 286.93457 2 269.886719
--3.当前系统参数配置 NAME TYPE VALUE ------------------------------------ ---------------------- ------------------------------ memory_target big integer 10G memory_max_target big integer 10G sga_max_size big integer 10G (该系统当前值设置有问题) sga_target big integer 0 pga_aggregate_target big integer 0
--4计划调整内存组件参数如下: --自动共享内存管理(ASMM) --注意这里是因为该系统是OLAP和OLTP功能混用,所以内存分配特殊 memory_target big integer 0 memory_max_target big integer 0 sga_max_size big integer 8G sga_target big integer 0 pga_aggregate_target big integer 10G shared_pool_size big integer 4G db_cache_size big integer 2G
--5.确认参数文件并于操作前备份参数文件 show parameter spfile;(操作前要有参数文件备份) NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ spfile string +DATEDG/rac11g/spfilerac11g.ora
create pfile='/home/oracle/oldpfile.ora' from spfile ='+DATEDG/rac11g/spfilerac11g.ora';
--6.修改内存组件参数: 1节点: alter system set memory_max_target=0 scope=spfile sid='*'; alter system set sga_max_size=8192M scope=spfile sid='rac11g1'; alter system set memory_target=0 sid='rac11g1'; alter system set sga_target=0 sid='rac11g1'; alter system set pga_aggregate_target=10240M sid='rac11g1'; shutdown immediate;
2节点: alter system set sga_max_size=8192M scope=spfile sid='rac11g2'; alter system set memory_target=0 sid='rac11g2'; alter system set sga_target=0 sid='rac11g2'; alter system set pga_aggregate_target=10240M sid='rac11g2'; shutdown immediate;
--7.使用跟新后的spfile创建pfile然后修改 节点1: 使用跟新后的spfile创建pfile然后修改 create pfile='/home/oracle/newpfile.ora' from spfile ='+DATEDG/rac11g/spfilerac11g.ora'; --8.注释(参见文档 ID 1397761.1) 注释: vi /home/oracle/newpfile.ora #*.memory_max_target=0 #rac11g1.memory_target=0 #rac11g2.memory_target=0
--9.使用修改后的newpfile重建参数文件(原spfile可以重命名备份): create spfile='+DATEDG/rac11g/spfilerac11g.ora' from pfile='/home/oracle/newpfile.ora';
--10.分别启动数据库 启动数据库(两节点分别启动): startup;
--11.确认参数设置情况(两节点): 确认参数设置情况(两节点): show parameter memory_max_target; show parameter sga_max_size; show parameter memory_target; show parameter sga_target; show parameter pga_aggregate_target;
--12.设置shared_pool_size和db_cache_size参数: 设置shared_pool_size和db_cache_size参数: 1节点: alter system set shared_pool_size=4096M sid='rac11g1'; alter system set db_cache_size= 2048M sid='rac11g1'; 2节点: alter system set shared_pool_size=4096M sid='rac11g2'; alter system set db_cache_size= 2048M sid='rac11g2';
--13.确认参数设置情况(两节点): 确认参数设置情况(两节点):
show parameter shared_pool_size; show parameter db_cache_size;
--14. 查看日志是否有报错信息: ---------- 备注: 参考文档: ORA-00843, ORA-00849 When Trying To Change SGA_TARGET With MEMORY_MAX_TARGET=0 Being Active (文档 ID 1397761.1)