TNS listener startup slow in oracle 11.1

Issue: listener start up is slow in oracle 11.1

When you do a strace/tusc trace you can see there is  lot of snlinGetAddrInfo calls made during dns queries and there are lot of sleep during these dns queries.

 

#tusc -r all -w all -v –aenfpo /tmp/Listener.out listener_startup_command

issue is even if host details available in the /etc/hosts oracle consults /etc/resolv.conf  for hostname lookup.

if  some of the dns servers not replying that queries will show as sleep or it will increase time out.

work around :-

1. we can add in /etc/hosts

     ipnodes: files

2. we can use environment variable  LOCALDOMAIN in oracle user's profile

LOCALDOMAIN=unixmemoirs.com
export LOCALDOMAIN

Real issue is a bug in oracle. Please find below links for explanation.

http://oradbastuff.blogspot.in/2011/06/connections-to-11g-tns-listener-are.html

http://www.askmaclean.com/archives/dns%E8%AE%BE%E7%BD%AE%E5%BC%95%E8%B5%B7%E7%9A%84%E7%99%BB%E5%BD%95%E5%BB%B6%E8%BF%9F.html