PHP-FPM no cache

[Maxim Dounin]

Hello!

On Mon, Jul 04, 2011 at 02:11:11AM -0500, HTF wrote:

> Hello,
> 
> I've enabled caching on php scripts as below but it looks like the
> server is not caching at all:
> 
> http {
>   fastcgi_cache_path   /tmp/cache  levels=1:2
>                        keys_zone=tmp:10m
>                        inactive=5m;
>  
>   server {
>     location / {
>       ...
>       fastcgi_cache   tmp;
>       fastcgi_cache_valid   any      1h;
>       fastcgi_cache_min_uses  1;
>       ...
>     }
>   }
> }
> 
> - but the caching directory is totally empty (nginx has write privileges
> as it was created by nginx itself during reload)
> - I haven't noticed any performance improvements by running apache
> benchmark from different machine

Check your php responses, most likely they disable cache: nginx 
honors Cache-Control, Expires headers, and additionally it will 
disable cache if it sees Set-Cookie header in response.  This 
behaviour may be overwritten if desired with 
fastcgi_cache_ignore_headers directive, see here:

http://wiki.nginx.org/HttpFcgiModule#fastcgi_ignore_headers

Note though that it's not generally safe as it may cause private 
pages (and/or cookies) to be cached and returned to other clients.  
Handle with care.

Maxim Dounin