1、查詢oracle的連接數(shù)
select count(*) from v$session;
2、查詢oracle的并發(fā)連接數(shù)
select count(*) from v$session where status='ACTIVE';
3、查看不同用戶的連接數(shù)
select username,count(username) from v$session where username is not null group by username;
4、查看所有用戶：
select * from all_users;
5、查看用戶或角色系統(tǒng)權(quán)限(直接賦值給用戶或角色的系統(tǒng)權(quán)限)：
select * from dba_sys_privs;
select * from user_sys_privs;
6、查看角色(只能查看登陸用戶擁有的角色)所包含的權(quán)限
select * from role_sys_privs;
7、查看用戶對象權(quán)限：
select * from dba_tab_privs;
select * from all_tab_privs;
select * from user_tab_privs;
8、查看所有角色：
select * from dba_roles;
9、查看用戶或角色所擁有的角色：
select * from dba_role_privs;
select * from user_role_privs;
10、查看哪些用戶有sysdba或sysoper系統(tǒng)權(quán)限(查詢時需要相應(yīng)權(quán)限)
select * from V$PWFILE_USERS;
修改數(shù)據(jù)庫允許的最大連接數(shù)：
alter system set processes = 300 scope = spfile;
查看游標(biāo)數(shù)量
Select * from v$open_cursor Where user_name=''
查詢數(shù)據(jù)庫允許的最大連接數(shù)：
select value from v$parameter where name = 'processes';
或者：show parameter processes;
查詢數(shù)據(jù)庫允許的最大游標(biāo)數(shù)：
select value from v$parameter where name = 'open_cursors'
查看oracle版本
select banner from sys.v_$version;
按降序顯示用戶"SYSTEM"為每個會話打開的游標(biāo)數(shù)
select o.sid, osuser, machine, count(*) num_curs from v$open_cursor o, v$session s where user_name = 'SYSTEM' and o.sid=s.sid group by o.sid, osuser, machine order by num_curs desc;