sqlish queries for cache invalidation?

Nils Goroll slink at schokola.de
Fri Jan 26 17:15:42 UTC 2018


On 26/01/18 17:07, Dridi Boukelmoune wrote:
> So if you need complex expressions and are ready to give up the
> real-time nature of xkey purges, you can reuse whatever headers (xkey
> supports a couple) that contain your invalidation keys and issue bans
> instead:
>     ban obj.http.xkey ~ project2 && obj.http.xkey ~ inst6
> Like I said, xkey gives up some of the ban flexibility and moves the
> cursor to real-time processing while bans are deferred by design.

Dridi, I completely agree with your response, except for one thing: IMHO, bans
are in no way less real time than purges: While the ban *lurker* processing is
deferred, actual ban checks at lookup time happen as immediately as whatever purges.

Other than that, purges act on objectheads ("cache keys") affect all variants
under that cache key. bans are checked per object (variant).


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