ORA-12519: TNS:no appropriate service handler found 解决

有时候连得上数据库,有时候又连不上.
可能是数据库上当前的连接数目已经超过了它能够处理的最大值.
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->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;