[Varnish] #510: Age of objects with 2 varnishes in front of each other

Varnish varnish-bugs at projects.linpro.no
Mon May 18 13:57:19 CEST 2009


#510: Age of objects with 2 varnishes in front of each other
----------------------+-----------------------------------------------------
 Reporter:  nicholas  |        Type:  defect
   Status:  new       |    Priority:  normal
Milestone:            |   Component:  build 
  Version:  trunk     |    Severity:  normal
 Keywords:            |  
----------------------+-----------------------------------------------------
 We have a setup with 2 varnishes in front of each other, "front" and
 "back". We want to cache an object for 180s and set:
 obj.ttl = 180s;
 set obj.http.cache-control = "s-maxage=180";

 in the back varnish. The front varnish starts counting Age at 0 and keeps
 the object 180s. By comparing objectid's we see that we are getting front
 180s + back (0 to 180s) cache times.

 In the source code of varnishd.c for 2.0.4 we see
 ...
          if (age > max_age)
                  ttl = 0;
          else
                  ttl = max_age - age;

 But we suspect that $age here is not valid, or ttl would have decreased
 accordingly.

 Bug?

 # varnishd -V
 varnishd (varnish-2.0.4)

 # rpm -qa | grep varnish
 varnish-libs-devel-2.0.4-1.el5
 varnish-2.0.4-1.el5
 varnish-debuginfo-2.0.4-1.el5
 varnish-libs-2.0.4-1.el5

 # cat /etc/issue
 Red Hat Enterprise Linux Server release 5.2 (Tikanga)

 x86_64 system.

 Poke me for more details, steps to reproduce or testing.

 :-)
 -nicholas

-- 
Ticket URL: <http://varnish.projects.linpro.no/ticket/510>
Varnish <http://varnish.projects.linpro.no/>
The Varnish HTTP Accelerator


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