Yep! Getting tons of uncacheable responses, including lots of /images/thumb URLs, due to negative TTLs. Not sure yet what the best way to handle this is since I'm sure this is done for a reason, so I'll need to dig back in to the MW code and possibly hit up the devs on IRC again. Thanks! I'll let you know how this goes.
Justin -----Original Message----- From: Dridi Boukelmoune [mailto:[email protected]] Sent: Tuesday, December 13, 2016 7:42 AM To: Justin Lloyd <[email protected]> Cc: Guillaume Quintard <[email protected]>; [email protected] Subject: Re: Hit ratio dropped significantly after recent upgrades On Tue, Dec 13, 2016 at 4:20 PM, Justin Lloyd <[email protected]> wrote: > That's really the crux of my problem, as I tried to summarize in my last big > email though it was longer than it probably should have been. Is it possible > to determine from varnishlog whether/which requests are being missed and > fetched but not cached? There are more things you can see with varnishlog like hashes for instance, but you could start by logging markers in your VCL to see which branches you are taking. Example: if (beresp.ttl <= 0s) { std.log("negative ttl"); set beresp.uncacheable = true; return (deliver); } And do the same for all branches, and see which code is executed. > I get the feeling that this will turn out to be either something very simple > in the Varnish and/or MediaWiki configuration or else a bug somewhere, though > I'd lean towards the former as being more likely. If you can reproduce it in lab conditions where you are the only user, look for a transaction containing: - VCL_return hash - VCL_call HASH - VCL_return lookup - VCL_call PASS And then look for the previous transaction on the same resource. Dridi _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
