Nginx cache grouped by keys

[Piotr Sikora]

Hello Wandenberg,
thank you for your patches and sorry for the late reply.

I've been toying with various ideas on how to improve cache purging 
mechanism (with prefixes, wildcards and/or cache groups) for the last 2 
years, but to be honest, I wasn't happy with any of them... And while your 
approach is probably the best you can do with current cache implementation, 
it's far from perfect, simply because it needs to walk the disk, which makes 
it useable only for very small cache groups.

If nginx guys decide that your approach is acceptable and include it in the 
core, then I have no problem with adding support for it in ngx_cache_purge, 
but to be honest, I would prefer to see some kind of persistent cache index 
instead ;)

Best regards,
Piotr Sikora < piotr.sikora at frickle.com >