Re: [Pdns-users] pdns_recursor 3.3-hooks ... possible cache issue
On Wed, Apr 13, 2011 at 11:53:35AM -0700, Alfred B. M. Cordero wrote: > Using the postresolve hook in lua to alter TTL that are too low. > I log queries that hit the lua code and I see log events for > that same host that occur within the same one second period > and sometimes within a few or more seconds. I don't understand > why there are multiples. Shouldn't they be cached and then served > from the cache? Hi Alfred, Try reproducing with 'threads=1'. You may be seeing hits from multiple separate caches. Bert ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
Re: [Pdns-users] pdns_recursor 3.3-hooks ... possible cache issue
On Wed, 13 Apr 2011 12:11:34 -0700 bert hubert wrote: >Try reproducing with 'threads=1'. You may be seeing hits from >multiple separate caches. You are telling me that each thread maintains its own cache. I restarted with threads=1 but I still see the same. Having higher resolution timestamps in syslog might reveal something but not sure as I see duplicate log entries over a few to several second time spans. Also it may be the way I print log events, I may need more info about the query and the reply. I will look into that. ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
Re: [Pdns-users] pdns_recursor 3.3-hooks ... possible cache issue
On Thu, Apr 14, 2011 at 09:40:58AM -0700, Alfred B. M. Cordero wrote: > On Wed, 13 Apr 2011 12:11:34 -0700 bert hubert > wrote: > >Try reproducing with 'threads=1'. You may be seeing hits from > >multiple separate caches. > > You are telling me that each thread maintains its own cache. > I restarted with threads=1 but I still see the same. Ok - in that case it may be good to know that the output of the Lua scripts is only cached in the packet cache, and not within the main dns cache. So whatever TTL you set, the result will not be cached for longer than packetcache-ttl seconds. And only for *exactly* identical questions. Perhaps this clarifies the situation? Bert ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
Re: [Pdns-users] pdns_recursor 3.3-hooks ... possible cache issue
On Thu, 14 Apr 2011 10:13:05 -0700 bert hubert wrote: >Ok - in that case it may be good to know that the output of the >Lua scripts is only cached in the packet cache, and not within the main dns cache. > >So whatever TTL you set, the result will not be cached for longer >than packetcache-ttl seconds. And only for *exactly* identical >questions. > >Perhaps this clarifies the situation? It does in some way. But it's like now I know I am in a rabbit hole and before I didn't know what hole. But I appreciate your time and consideration on it and I will read more about it. I see log events like TTL 835 for mail1.example.com (of course the log events are formated by me) 14:23:33 Altering TTL 865 for mail1.example.com 14:23:33 Altering TTL 865 for mail1.example.com 14:23:34 Altering TTL 864 for mail1.example.com 14:23:34 Altering TTL 864 for mail1.example.com 14:23:34 Altering TTL 864 for mail1.example.com 14:23:35 Altering TTL 863 for mail1.example.com Disabling packet-cache offers no relief and I guess it is a feature. ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
