今天现场维护人员报告说数据库连接不上，PLSQL连接无响应。登陆数据库服务器后输入lsnrctl status就卡住了。

查下监听日志，主要是以下内容：

TNS-12525: TNS:listener has not received client's request in time allowed
TNS-12535: TNS:operation timed out
  TNS-12606: TNS: Application timeout occurred

TNS-12518: TNS:listener could not hand off client connection
TNS-12571: TNS:packet writer failure
  TNS-12560: TNS:protocol adapter error
   TNS-00530: Protocol adapter error
    Linux Error: 104: Connection reset by peer

27-NOV-2012 15:43:26 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=oracle))(SERVICE_NAME=orcl)) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.10.1.200)(PORT=61018)) * establish * orcl * 0

数据库警告日志中也出现ora-609内容：

Fatal NI connect error 12537, connecting to:
(LOCAL=NO)

VERSION INFORMATION:
TNS for Linux: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
Time: 29-FEB-2012 20:45:05
Tracing not turned on.
Tns error struct:
ns main err code: 12537
TNS-12537: TNS:connection closed
ns secondary err code: 12560
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (12792) as a result of ORA-609

重启监听后问题重现。

 

解决方法，参考百度和谷歌的结果:

注释掉/etc/resolve.conf 中对DNS解析内容。

重启监听，OK.

 

原因：

oracle bug：

Bug 9593134 - DNS or NIS mis-configuration can cause slow database connects [ID 9593134.8]