select count(*) from v$process --当前的连接数 select value from v$parameter where name = 'processes' --数据库允许的最大连接数 修改最大连接数: alter system set processes = 300 scope = spfile; 重启数据库: shutdown immediate; startup; --查看当前有哪些用户正在使用数据 SELECT osuser, a.username,cpu_time/executions/1000000||'s', sql_fulltext,machine from v$session a, v$sqlarea b where a.sql_address =b.address order by cpu_time/executions desc;