On Wed, Jan 26, 2011 at 10:32:19AM +0100, Christian Kuehn wrote: > Hi, Hey there,
> any idea why the pdns-recursor 3.3 gives different answers to the same > query?? > Looks like a bug?? The recursor now scales over CPUs and cores by default and maintains a cache per 'thread', hence it _might_ give different answers from cache on occasion. -> http://doc.powerdns.com/changelog.html#changelog-recursor-3-2 "Multithreading, allowing near linear scaling to multiple CPUs or cores. Configured using 'threads=' (many commits). This also deprecates the '--fork' option." "This version of the PowerDNS Recursor contains a rather novel form of lock-free multithreading, a situation that comes close to the old '--fork' trick, but allows the Recursor to fully utilize multiple CPUs, while delivering unified statistics and operational control. In effect, this delivers the best of both worlds: near linear scaling, with almost no administrative overhead. Compared to 'regular multithreading', whereby threads cooperate more closely, more memory is used, since each thread maintains its own DNS cache. However, given the economics, and the relatively limited total amount of memory needed for high performance, this price is well worth it." So it's not a bug, but by design. In normal DNS operations you should not get different responses, however your example seems to be one of those edge cases where you do. I'm getting a REFUSED from both pns.dtag.de and secondary000.dtag.net for that query btw. Note that you can also fire up the recursor with the trace=yes option in order to find out where exactly the recursion process goes haywire, however be advised that this causes a _lot_ of logging output. Stefan -- The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair. - Douglas Adams, "Mostly Harmless" _______________________________________________ Pdns-users mailing list [email protected] http://mailman.powerdns.com/mailman/listinfo/pdns-users
