ORA-12519, TNS:no appropriate service handler found

select count(*) from v$process --当前的连接数  130

select value from v$parameter where name = ‘processes‘ --数据库允许的最大连接数,默认150

--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;