how to disable nginx internal dns cache?

[nevernet]

i have resolver define, see below configuration:

server {
 listen   80;
 server_name  xx.com;
 access_log  /var/log/nginx/xx-nginx.access.log;
 error_log  /var/log/nginx/xx-nginx_error.log debug;

# resolver 8.8.8.8;
# resolver_timeout 1s;

 #set your default location
 location / {
#  resolver 8.8.8.8 valid=5s;  # i have defined resolver at here ,and also
tried to add it in "http" section in nginx.conf file.   but both of them
doesnt work. 
  proxy_pass         http://p2.domain.com;
 }

 #error_page  404  /404.html;
  # redirect server error pages to the static page /50x.html
 #
 error_page   500 502 503 504  /50x.html;
 location = /50x.html {
  root   /var/www;
 }
}

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,238835,238893#msg-238893