【Case】ORA-12519: TNS:no appropriate service handler found

今天有AP用戶反映，數(shù)據(jù)庫(kù)有時(shí)候連的上，有時(shí)候連不上，報(bào)如下的錯(cuò)誤：

ORA-12519: TNS:no appropriate service handler found

二、原因解析

oracle@C01TEST03:/home/oracle>oerr ORA 12519
12519, 00000, "TNS:no appropriate service handler found"
// *Cause: The listener could not find any available service handlers that
// are appropriate for the client connection.
// *Action: Run "lsnrctl services" to ensure that the instance(s) have
// registered with the listener, and are accepting connections.

第一個(gè)原因可能是Instance沒(méi)有注冊(cè)到Listener；

第二個(gè)原因可能是數(shù)據(jù)庫(kù)上當(dāng)前的連接數(shù)目已經(jīng)超過(guò)了它能夠處理的最大值。

三、解決方法

根據(jù)第二步，檢查兩個(gè)地方：

1、查看Instance是否注冊(cè)到Listener

oracle@C01TEST03:/home/oracle>lsnrctl status

LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 03-NOV-2017 15:29:45

Copyright (c) 1991, 2013, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=C01TEST03)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date                25-AUG-2017 13:37:06
Uptime                    70 days 1 hr. 52 min. 38 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /oracle/product/11.2.0/network/admin/listener.ora
Listener Log File         /oracle/product/diag/tnslsnr/C01TEST03/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=C01TEST03)(PORT=1521)))
Services Summary...
Service "MTH" has 1 instance(s).
  Instance "MTH", status READY, has 1 handler(s) for this service...

確認(rèn)到"MTH" Instance已經(jīng)注冊(cè)到listener里了；

2、數(shù)據(jù)庫(kù)上當(dāng)前的連接數(shù)目已經(jīng)超過(guò)了它能夠處理的最大值。

(1)查看當(dāng)前連接數(shù)

SQL> select count(*) from v$process；

查看數(shù)據(jù)庫(kù)允許最大的連接數(shù)

SQL> show parameter processes;

(2)適當(dāng)加大processes的值

alter system set processes = 300 scope = spfile;

(3)重啟數(shù)據(jù)庫(kù)

(4)查看當(dāng)前有哪些用戶正在使用數(shù)據(jù)
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;

四、問(wèn)題總結(jié)

   以上便是該問(wèn)題的思考及處理方向。處理方法以第二種，修改參數(shù)processes的方法為主。