oracle基本参数查询

1.查看当前数据库建立的进程情况：
select count(*) from vKaTeX parse error: Expected 'EOF', got '#' at position 27: …lect sid,serial#̲,username,progr…session;
select program,username,count(1) from v$session group by program,username order by count(1) desc;

----会话连接数
select count(1) from v$session;

------会话连接数最大值
select value from v$parameter where name=‘sessions’;

2.查询数据库当前进程的连接数
select b.MACHINE, b.PROGRAM , count() from v$processa,v$session b where a.ADDR = b.PADDR and b.USERNAME is not null group by b.MACHINE , b.PROGRAM order by count() desc;
3.查询数据库允许的最大连接数
select value from v$parameterwherename{=}^{\prime }processe{s}^{\prime };或者：showparameterprocesses;4.修改数据库允许的最大连接数altersystemsetprocesses=300scope=spfile;5.重启数据库shutdownimmediate;startup;6.查看连接oracle的所有机器的连接数和状态selectmachine,status,count(\ast )fromv$sessiongroup by machine,statusorder by status;
7.查看oracle进程的使用
SELECt PROGRAM, PGA_USED_MEM, PGA_ALLOC_MEM, PGA_FREEABLE_MEM, PGA_MAX_MEM FROM V$PROCESS;8.查看不同用户的连接数selectusername,count(username)fromv$session where username is not null group by username;
9.查看所有用户
select * from all_users;
10.修改数据库允许的最大连接数
alter system set processes = 300 scope = spfile;
查看游标数量
Select * from v$ope{n}_{c}ursorWhereuse{r}_{n}ame{=}^{\prime \prime }查询数据库允许的最大连接数：selectvaluefromv$parameter where name = ‘processes’;
或者：show parameter processes;
查询数据库允许的最大游标数：
select value from vKaTeX parse error: Expected group after '_' at position 74: …nner from sys.v_̲version;
按降序显示用户"SYSTEM"为每个会话打开的游标数
select o.sid, osuser, machine, count(*) num_curs from v$ope{n}_{c}ursoro,v$session s where user_name = ‘SYSTEM’ and o.sid=s.sid group by o.sid, osuser, machine order by num_curs desc;
11.设置数据库密码永不过期
ALTER profile DEFAULT limit PASSWORD_LIFE_TIME UNLIMITED