Nginx generating different md5 sums for same key causing cache to become corrupt

Server NGINX
1

Hello,
Currently we use nginx 1.8.1 on redhat 7. We have reverse proxy
caching
enabled but are experiencing unexpected behaviour. Our caching key is
$scheme$request_method$host$request_uri$. On the first visit to a page,
a
cache file with the correct md5 sum of the key is created. If you visit
the
same url from the same browser, but a different tab, a new cache file is
created with different md5 sum, but same content. The next time you
visit
the url from that browser, it will be random which page is selected from
the
cache. Now if you visit from a second browser a 3rd cache file will be
created. Reloading from any browser or tab will randomly pick one of
the
created files. Are there other factors in creating the md5 other than
the
cache key ?

Posted at Nginx Forum:

2

Hello!

On Tue, Mar 29, 2016 at 08:36:37AM -0400, pirish wrote:

created files. Are there other factors in creating the md5 other than the
cache key ?

When a response uses Vary mechanism, multiple representation may
be stored in cache under secondary cache keys derived from the
request headers listed in Vary. You can use proxy_ignore_headers
to instruct nginx to ignore Vary headers in response, see
Module ngx_http_proxy_module.

–
Maxim D.
http://nginx.org/