使用数据链时报错ora-12545/tns-12545的重现和解决
1. 查看 tnsnames.ora中条目 ：
linux_dblk =
(description =
(address = (protocol = tcp)(host = linux.linuxidc.com)(port = 1521))
(connect_data =
(server = dedicated)
(service_name = linux)
)
)
/etc/hosts中不写linux.linuxidc.com与ip的对应，，也无法通过dns得到linux.linuxidc.com的ip。
2.创建数据链并使用linuxidc@ linuxidcrac1>create database link linux_db connect to test9 identified by test9 using 'linux_dblk';
database link created.
此时使用dblink: 执行了很长时间，报错：ora-12545:connect failed because target host or object does not exist
21:42:57 linuxidc@ linuxidcrac1>select * from test9@linux_db;
select * from test9@linux_db
*
error at line 1:
ora-12545: connect failed because target host or object does not exist
elapsed: 00:02:40.25
###########3
3.查看日志中报错信息：[oracle@linuxidcrac1 ~]$ cat alert_linuxidcrac1.log
创建和使用数据链时会有类似如下报错日志： --截取部分
sat dec 28 21:41:29 2013
***********************************************************************
fatal ni connect error 12545, connecting to:
(description=(address=(protocol=tcp)(host=racdg)(port=1521))(connect_data=(server=dedicated)(service_name=racdg)(cid=(program=oracle)(host=linuxidcrac1.linuxidc.com)(user=oracle))))
version information:
tns for linux: version 11.2.0.1.0 - production
tcp/ip nt protocol adapter for linux: version 11.2.0.1.0 - production
time: 28-dec-2013 21:41:29
tracing not turned on.
tns error struct:
ns main err code: 12545
tns-12545: connect failed because target host or object does not exist
ns secondary err code: 12560
nt main err code: 515
tns-00515: connect failed because target host or object does not exist
nt secondary err code: 110
nt os err code: 0
###########
4.解决方法：/etc/hosts中增加相应条目：
192.168.1.211 linux.linuxidc.com linux
ping linux.linuxidc.com 测试正常。
linuxidc@ linuxidcrac1>select * from test9@linux_db;
aa
----------
dblink-ok ---此时重新登陆数据库,使用数据链正常：
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