Cannot figure out why I am getting a miss on a static URL

Dridi Boukelmoune dridi.boukelmoune at zenika.com
Fri Jan 16 16:26:11 CET 2015


What I mean is, post enough VCL to reproduce the issue, and maybe
varnishlog logs showing what's happening. If your vcl_fetch really
returns "deliver" unconditionally, you're probably doing something
wrong.

Dridi

On Fri, Jan 16, 2015 at 4:07 PM, Jennings III, Raymond
<raymond.jennings at nytimes.com> wrote:
> varnishncsa clearly shows hits and misses within a 24 hour period despite
> clearly setting the TTL to 24 hours.  Varnishlog clearly shows the TTL being
> set to 24 hours.  I have NO lru_nuked objects as clearly shown by the
> varnish stats.
>
> I'm not sure what is vague.  I am setting an object for a TTL of 24 hours
> yet during that 24 hour period it is still getting miss requests.  The URLs
> in question have no GET parameters.  I am hashing only on the URL and not
> the hostname.
>
> So what does this tell me?  It tells me that my cache size is big enough.
>
> My guess is there is some type of contention from locking of some type given
> other requests coming through.  There are quite a few PUT and POST requests
> that pass through this Varnish server.
>
> Ummmm, I hardly think that "anyone can't help me."  I think most definitely
> "someone" that has some insight about the internals could shed some light on
> this problem.
>
>
>
> Raymond Jennings III
> nytimes.com
> Office: 212.556.7786
> iPhone: 914.330.5074
> E-mail: Raymond.Jennings at nytimes.com
> FaceTime: Raymond.Jennings at nytimes.com
>
> On Fri, Jan 16, 2015 at 10:01 AM, Dridi Boukelmoune
> <dridi.boukelmoune at zenika.com> wrote:
>>
>> Hi Raymond,
>>
>> Have you looked at the logs?
>>
>> Your description of the issue is too vague, I don't think anyone can
>> help you with just that.
>>
>> Cheers,
>> Dridi
>>
>> On Thu, Jan 15, 2015 at 3:36 PM, Jennings III, Raymond
>> <raymond.jennings at nytimes.com> wrote:
>> > I have a static URL that I set a TTL for 24h but yet every so many
>> > minutes I
>> > get a "miss" (as shown in my varnishncsa.)
>> >
>> > I purge this URL every 24 hours.
>> >
>> > 1 - The URL never has any parameters.
>> > 2 - I do not hash over the hostname only the URI
>> > 3 - Nobody is issuing any PURGE or BAN requests
>> > 4 - n_lru_nuked is always 0
>> > 5 - There are no 500 or 400 responses
>> >
>> > What is causing this URL to get a miss when everything I see looks good?
>> > If
>> > the cache size has been exceeded I would have expected to see the nuked
>> > value be something other than 0.
>> >
>> > vcl_fetch is basically just:
>> >
>> > set beresp.ttl = 24h;
>> > return(deliver);
>> >
>> > Any reason why Varnish seems to be taking it upon itself to cause this
>> > miss?
>> > In 24 hours I get about 12000 requests and out of those 120 misses and I
>> > should see 2 miss requests at most.
>> >
>> > The backends are healthy.
>> >
>> > This is varnish-3.0.6-1.el6.x86_64
>> >
>> > Thanks.
>> >
>> >
>> >
>> > Raymond Jennings III
>> > nytimes.com
>> > Office: 212.556.7786
>> > iPhone: 914.330.5074
>> > E-mail: Raymond.Jennings at nytimes.com
>> > FaceTime: Raymond.Jennings at nytimes.com
>> >
>> > _______________________________________________
>> > varnish-misc mailing list
>> > varnish-misc at varnish-cache.org
>> > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>
>



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