简单查看oracle的连接情况和内存使用情况

select machine,count(*) from v$session group by machine; 

select machine,status,count(*) from v$session group by machine,status order by status; 

select 'SGA' AS NAME,ROUND(sum(value)/1024/1024,2)||'M' AS "SIZE(M)" from v$sga 
UNION 
select 'PGA' AS NAME,ROUND(value/1024/1024,2)||'M' AS "SIZE(M)" from v$pgastat where name='total PGA allocated' 
UNION 
select 'TOTAL' AS NAME,((SELECT ROUND(sum(value)/1024/1024,2) from v$sga)+(select ROUND(value/1024/1024,2) from v$pgastat where name='total PGA allocated'))||'M' AS "SIZE(M)" FROM DUAL 
UNION 
SELECT NAME,TO_CHAR(VALUE) FROM V$PGASTAT WHERE NAME='process count'; 

ALTER SYSTEM SET MEMORY_TARGET = 1024M SCOPE=SPFILE; 
ALTER SYSTEM SET memory_max_target = 1500M SCOPE=SPFILE; 
ALTER SYSTEM SET SGA_TARGET = 0 SCOPE=SPFILE; 
ALTER SYSTEM SET SGA_MAX_SIZE=800M SCOPE=SPFILE; 
ALTER SYSTEM SET PGA_AGGREGATE_TARGET = 0 SCOPE=SPFILE; 
alter system set pre_page_sga=FALSE scope=spfile;