> What would be too many objects linked to a single key? To be honest, I don't > know. For an answer we'll need to invoke the VMOD authors :)
Keys are just tags, so you could really tag responses in many ways. For example, on a server delivering contents for multiple hosts, you could use the normalized host name as a key and decide that any release on the backend side should invalidate the cache of the associated host. Another common example is tagging responses by type, for example add an "article" key. Once you change your articles template, you have a way to soft-purge all the cached articles. No, there are no implicit limits in vmod-xkey. Yes, there are related limits as pointed out by Carlos, namely number and size of response headers. vmod-xkey allows criteria-based invalidation like bans (but not as versatile) at a purge-like scale, and besides the additional memory footprint it can exhibit contention when the set of purged keys invalidate too many objects. I'm afraid I don't have any numbers to share regarding when things go out of hand. Varnish has a "cutoff" parameter for bans but vmod-xkey has nothing of the sort to keep everything under tight control. Dridi PS. not the vmod-xkey author _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
