记录一则数据库连接故障ORA-12560,ORA-12518

环境：Win Server 2008 R2 + Oracle 11.2.0.1

故障：客户反映数据库连接不上，本机sysdba和网络连接都连接不上。

一、确认故障

• 1.1 服务器尝试sysdba登录
• 1.2 服务器尝试通过网络连接

二、排查原因

• 2.1 ORA-12560错误初步排查原因
• 2.2 ORA-12518错误排查原因
• 2.3 ORA-12560错误再次排查原因

一、确认故障

1.1 服务器尝试sysdba登录

```
PS C:\Users\Administrator> sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on 星期四 2月 18 09:39:14 2016

Copyright (c) 1982, 2010, Oracle. All rights reserved.

ERROR:

ORA-12560: TNS: 协议适配器错误

<h2 id="1.2">1.2 服务器尝试通过网络连接</h2>

PS C:\Users\Administrator> sqlplus system/oracle@xxoradb

SQL*Plus: Release 11.2.0.1.0 Production on 星期四 2月 18 09:34:01 2016

Copyright (c) 1982, 2010, Oracle. All rights reserved.

ERROR:

ORA-12518: TNS: 监听程序无法分发客户机连接

<h1 id="2">二、排查原因</h1>
<h2 id="2.1"> 2.1 ORA-12560错误初步排查原因 </h2>
ORA-12560错误官方说明：

$ oerr ora 12560

12560, 00000, "TNS:protocol adapter error"

// *Cause: A generic protocol adapter error occurred.

// *Action: Check addresses used for proper protocol specification. Before

// reporting this error, look at the error stack and check for lower level

// transport errors. For further details, turn on tracing and reexecute the

// operation. Turn off tracing when the operation is complete.

MOS相关文档：Bequeath connection fails with ORA-12560 on Windows (文档 ID 1986438.1)
可能原因：
> Environmental variables are not set correctly. This is a common issue on Windows.
> The following commands do not show proper settings:
>  echo %ORACLE_HOME%
>  echo %ORACLE_SID%
>  echo %PATH%

解决方法：
> Please do the following:
>
>  set ORACLE_HOME=                               <<<<< enter the Oracle Home path here
>  set ORACLE_SID=                                <<<<< enter the Oracle SID name here
>  set PATH=%PATH%;                               <<<<< add the path of %ORACLE_HOME%/bin <<<<< this is the directory where "sqlplus.exe" exists
>  echo %ORACLE_HOME%                             <<<<< this verifies the Oracle home value
>  echo %ORACLE_SID%                              <<<<< this verifies the Oracle SID value

可是<font color="red">目前情况是，环境变量ORACLE_SID设置没有问题。而Windows环境，ORACLE_HOME并不需要在环境变量中设置，而是在注册表中</font>
关于这个ORACLE_HOME环境变量的问题可参考MOS的另一篇文章：How to Set or Switch Oracle Homes on Windows (Doc ID 969581.1)

由于业务目前已经是中断状态，所以可以重启监听和数据库服务，检查注册表信息，但问题依旧。
这里实际走了弯路，因为sqlplus命令是正常使用的，所以在环境变量方面就没多想PATH的问题。

<h2 id="2.2">2.2 ORA-12518错误排查原因 </h2>
ORA-12518错误官方说明：

$ oerr ora 12518

12518, 00000, "TNS:listener could not hand off client connection"

// *Cause: The process of handing off a client connection to another process

// failed.

// *Action: Turn on listener tracing and re-execute the operation. Verify

// that the listener and database instance are properly configured for

// direct handoff. If problem persists, call Oracle Support.

// *Comment: The problem can be worked around by configuring dispatcher(s)

// to specifically handle the desired presentation(s), and connecting

// directly to the dispatcher, bypassing the listener.

查看当前监听配置文件：

listener.ora Network Configuration File: D:\app\Administrator\product\11.2.0\dbhome_1\network\admin\listener.ora

Generated by Oracle configuration tools.

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(SID_NAME = CLRExtProc)

(ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1)

(PROGRAM = extproc)

(ENVS = "EXTPROC_DLLS=ONLY:D:\app\Administrator\product\11.2.0\dbhome_1\bin\oraclr11.dll")

)

)

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = WIN-1XXXXXXXXXX)(PORT = 1521))

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC521))

)

)

ADR_BASE_LISTENER = D:\app\Administrator

修改监听配置文件加入静态监听配置内容：

listener.ora Network Configuration File: D:\app\Administrator\product\11.2.0\dbhome_1\network\admin\listener.ora

Generated by Oracle configuration tools.

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(SID_NAME = CLRExtProc)

(ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1)

(PROGRAM = extproc)

(ENVS = "EXTPROC_DLLS=ONLY:D:\app\Administrator\product\11.2.0\dbhome_1\bin\oraclr11.dll")

)

(SID_DESC =

(GLOBAL_DBNAME = xxoradb)

(ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1)

(SID_NAME = xxoradb)

)

)

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = WIN-1XXXXXXXXXX)(PORT = 1521))

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC521))

)

)

ADR_BASE_LISTENER = D:\app\Administrator

重启监听后再测试，发现加入静态监听后可以连接到数据库了，同时服务器上的PL/SQL工具也可以正常连接到数据库了。

C:\Users\Administrator>sqlplus system/oracle@xxoradb

SQL*Plus: Release 11.2.0.1.0 Production on 星期四 2月 18 10:52:24 2016

Copyright (c) 1982, 2010, Oracle. All rights reserved.

连接到:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL>

<font color="red">这样，就先解决了客户端网络连接的问题。</font>
<h2 id="2.3">2.3 ORA-12560错误再次排查原因</h2>上面解决了客户端的连接问题，但问题还没有完美解决，因为目前本地sysdba仍然还是无法登陆，依然报错ORA-12560：

C:\Users\Administrator>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on 星期四 2月 18 10:59:11 2016

Copyright (c) 1982, 2010, Oracle. All rights reserved.

ERROR:

ORA-12560: TNS: 协议适配器错误

请输入用户名:

<font color="red">这时候就怀疑可能是机器上安装了多个Oracle程序导致，也就是说这个sqlplus命令可能是某个客户端的sqlplus程序，</font>
下面验证下是不是这个情况：

看到Oracle产品目录下，11.2.0文件夹下有多个文件夹存在

D:\app\Administrator\product\11.2.0>dir

驱动器 D 中的卷没有标签。

卷的序列号是 0A43-E08A

D:\app\Administrator\product\11.2.0 的目录

2016/01/26 12:26 .

2016/01/26 12:26 ..

2016/01/26 12:35 client_1

2016/01/26 12:23 dbhome_1

2016/01/26 12:25 dbhome_2

0 个文件 0 字节

5 个目录 200,137,936,896 可用字节

看起来的确安装有多个Oracle软件，从命名规则来看，应该是1个客户端，两个DB。

查看当前系统注册表中ORACLE_HOME的值为`D:\app\Administrator\product\11.2.0\dbhome_1`
那么我们使用的sqlplus程序是不是这个路径下的呢？
进一步查看系统环境变量PATH的值，

D:\app\Administrator\product\11.2.0\client_1\BIN;D:\app\Administrator\product\11.2.0\dbhome_1\BIN;D:\app\Administrator\product\11.2.0\dbhome_1;C:\Program Files (x86)\Common Files\NetSarang;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\

<font color="red">果然第一个查找路径是客户端的，不是我们想要的服务端程序路径，第二个路径才是。</font>
现在问题就明朗了，我们把客户端的这个路径`D:\app\Administrator\product\11.2.0\client_1\BIN;`删掉。
然后重新打开cmd，发现已经可以正常sysdba登录

C:\Users\Administrator>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on 星期四 2月 18 11:16:53 2016

Copyright (c) 1982, 2010, Oracle. All rights reserved.

连接到:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL>

最后，再确认下，PL/SQL等工具也可以重新正常登录。至此，问题完美解决。