//當前的數據庫連接數
select count(*) from v$process;
//數據庫最大連接數 select value from v$parameter where name='processes';
//修改最大連接數:1000
alter system set processes = 1000 scope = spfile;
//當前會話數量
select count(*) from v$session;
//會話數量上限
select value from v$parameter where name = 'sessions';