What does open_file_cache_events do?

Maxim Dounin mdounin at mdounin.ru
Wed May 12 16:16:35 MSD 2010


On Wed, May 12, 2010 at 06:57:24AM -0400, Costello wrote:

> I'm looking to document directives that are missing from the Wiki.
> I found loads in the source code, especially thanks to Manlio Perillo.
> I've stumbled upon "open_file_cache_events" declared in ngx_http_core_module.c.
> I investigated what this does, here is what I found:
> - it's a on/off directive
> - it's off by default
> - its main purpose is from 1 file, ngx_open_file_cache.c


> Now I understand what the open file cache does, but I don't 
> understand what exactly what this directive does.
> When the directive is enabled, does Nginx process some kind of 
> event-based cache invalidation?
> Eg. Nginx would subscribe to events for this file, when the file 
> is deleted, Nginx gets notified with an event, and then updates 
> the cache entry?

Yes, it activates event based watching for file descriptor changes 
instead of periodic checks; available with kqueue event method.

It's intentionally left undocumented.  Don't use it, it's 
unfinished code (there are known race which leads to SIGSEGV).

Maxim Dounin

More information about the nginx mailing list