Nginx cache wired behavior

Hello.
I have the following problem:
When static cached file is changed, nginx returns it to client after
very long timeout. Great delay can be seen after receiving all file
content on the client (client receives all file data from server at
20:03:01, sends ack, and then receives Fin packet at 20:04:00).

I don’t see any related errors in error.log. How can I debug this issue?

Server config is the following:

server {
listen 80; ## listen for ipv4
server_name …;
access_log off;
client_body_buffer_size 128k;

     open_file_cache max=2048 inactive=600s;
     open_file_cache_valid 2000s;
     open_file_cache_min_uses 1;

open_file_cache_errors on;

     location ~ /\.(ht|svn) {
             deny  all;
     }

     location ~ \.(lib|inc|admin|handler|action|sql|log)$ {
             deny  all;
     }

     location ~ /(crons|scripts|shared)/ {
             deny all;
     }


     location ~ \.php$ {

limit_conn one 2;

             include       fastcgi_params;
             fastcgi_index       index.php;
             fastcgi_param       SCRIPT_FILENAME

/path/to/www$fastcgi_script_name;
fastcgi_buffer_size 64k;

fastcgi_buffer_size 4k;

             fastcgi_buffers 32 256k;

fastcgi_buffers 1024 4k;

              if ($uri !~ "^/images/") {

fastcgi_pass

unix:/var/run/fastcgi-mhouse-pool;
fastcgi_pass mhouse_fastcgi;
}
}

     location / {
             root   /path/to/www;
             index  index.php;
     }

}

$ uname -a
Linux hostname.provided.here 2.6.35-28-generic #50-Ubuntu SMP Fri Mar 18
18:42:20 UTC 2011 x86_64 GNU/Linux

$ nginx -V
nginx version: nginx/0.7.67
TLS SNI support enabled
configure arguments: --conf-path=/etc/nginx/nginx.conf
–error-log-path=/var/log/nginx/error.log
–http-client-body-temp-path=/var/lib/nginx/body
–http-fastcgi-temp-path=/var/lib/nginx/fastcgi
–http-log-path=/var/log/nginx/access.log
–http-proxy-temp-path=/var/lib/nginx/proxy
–lock-path=/var/lock/nginx.lock --pid-path=/var/run/nginx.pid
–with-debug --with-http_dav_module --with-http_flv_module
–with-http_geoip_module --with-http_gzip_static_module
–with-http_realip_module --with-http_stub_status_module
–with-http_ssl_module --with-http_sub_module --with-ipv6 --with-mail
–with-mail_ssl_module
–add-module=/build/buildd/nginx-0.7.67/modules/nginx-upstream-fair


Best regards,
Alexander Pyhalov,
system administrator of Computer Center of Southern Federal University

On 06/20/2011 20:18, Alexander Pyhalov wrote:

Hello.
I have the following problem:
When static cached file is changed, nginx returns it to client after
very long timeout. Great delay can be seen after receiving all file
content on the client (client receives all file data from server at
20:03:01, sends ack, and then receives Fin packet at 20:04:00).

Some more info: first time file is returned quickly. Then, if you edit
file, you receive this behavior. When cache is turned off, the delay
disappears.

С уважением,
Александр Пыхалов,
системный администратор ЮГИНФО ЮФУ.