How does Nginx look-up cached resource?

Maxim Dounin mdounin at
Thu Sep 10 15:33:38 UTC 2015


On Thu, Sep 10, 2015 at 05:07:36PM +0200, Sergey Brester wrote:

> Leave header format unchanged (I mean changes in header file
> 'src/http/ngx_http_cache.h'), but not calculate and not compare crc32
> (unused / reserved up to "change cache header format next time")?

Even that way resulting cache files will not be compatible with 
older versions which do the check, thus breaking upgrades (when 
cache items can be used by different versions simultaneously for a 
short time) and, more importantly, downgrades (which sometimes 
happen due to various reasons).

Maxim Dounin

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