ORA-12519 TNS no appropriate service handler found

該問題是由於資料庫的連線數不夠造成

1)當前的連線數

select count(*) from v$process;

2)資料庫允許的最大連線數

select value from v$parameter where name = 'processes';

3)修改最大連線數:

alter system set processes = 300 scope = spfile;

4)重啟資料庫:

shutdown immediate;

startup;

5)檢視當前有哪些使用者正在使用資料

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;