[Pdns-users] First Alpha Release of PowerDNS Recursor 4.9.0

Otto Moerbeek otto.moerbeek at open-xchange.com
Wed Apr 12 09:18:23 UTC 2023


   We are proud to announce the first alpha release of PowerDNS Recursor

   Compared to the previous major (4.8) release of PowerDNS Recursor, this
   release contains the following major changes:

     * The performance impact of metrics collection has been reduced by
       using lock-free non-atomic thread-local counters.
     * The packet cache is sharded and shared by all threads.
     * The TTL of negative answers in the packet cache can now be
       controlled separately from positive and failure answers.
     * The rec_control trace_regex command writes the generated trace
       information to a specified file instead of the general log. The
       trace information contains more precise timestamps and DNSSEC
       validation information.
     * If [1]extended-resolution-errors is enabled EDNS errors are now
       generated in more cases, specifically when authoritative servers
       for a zone are unreachable or when synthesising answers by e.g.
       using the aggressive NSEC cache.
     * The aggressive NSEC cache has been changed to not store NSEC3
       entries which cover only a small [2]fraction of possible names.

  Feedback is appreciated!

   As a follow-up to the shared packet cache, the default way the recursor
   distributes requests over worker threads has now been changed to let
   the operating system kernel do that, by changing the defaults of
   [3]pdns-distributes-queries to no and [4]reuseport to yes. Though our
   testing has shown benefits to this approach, we have seen that in some
   rare cases (depending on OS and client traffic patterns) this can have
   negative consequences: the queries are not distributed equally over the
   worker threads. If you are running this alpha release we would
   appreciate your feedback, to be able to confirm the change of defaults
   benefits the vast majority of cases. Watch the periodic statistics
   printed by the recursor to see if the worker threads process about
   equal amounts of queries. Especially if you see an imbalance, send us
   details about the OS, hardware and configuration.

   As always, there are also many smaller bug fixes and improvements,
   please refer to the [5]changelog for additional details. When upgrading
   do not forget to check the [6]upgrade guide.

   Please send us all feedback and issues you might have via
   the [7]mailing list, or in case of a bug, via [8]GitHub.

   The [9]tarball ([10]signature) is available from our download
   [11]server and packages for several distributions are available from
   our [12]repository.

   With the future final 4.9.0 release, the 4.6.x releases will be EOL and
   the 4.7.x and 4.8.x releases will go into critical fixes only mode.
   Consult the EOL [13]policy for more details.

   We would also like to mention that with the 4.5 release we stopped
   supporting systems using 32-bit time. This includes many 32-bit Linux

   We are grateful to the PowerDNS community for the reporting of bugs,
   issues, feature requests, and especially to the submitters of fixes and
   implementations of features.


   1. https://docs.powerdns.com/recursor/settings.html#extended-resolution-errors
   2. https://docs.powerdns.com/recursor/settings.html#aggressive-cache-min-nsec3-hit-ratio
   3. https://docs.powerdns.com/recursor/settings.html#pdns-distributes-queries
   4. https://docs.powerdns.com/recursor/settings.html#reuseport
   5. https://doc.powerdns.com/recursor/changelog/4.9.html#change-4.9.0-alpha1
   6. https://docs.powerdns.com/recursor/upgrade.html
   7. https://mailman.powerdns.com/mailman/listinfo/pdns-users
   8. https://github.com/PowerDNS/pdns/issues/new/choose
   9. https://downloads.powerdns.com/releases/pdns-recursor-4.9.0-alpha1.tar.bz2
  10. https://downloads.powerdns.com/releases/pdns-recursor-4.9.0-alpha1.tar.bz2.sig
  11. https://downloads.powerdns.com/releases/
  12. https://repo.powerdns.com/
  13. https://docs.powerdns.com/recursor/appendices/EOL.html


kind regards,
Otto Moerbeek
PowerDNS Developer

Email: otto.moerbeek at open-xchange.com

Open-Xchange AG, Hohenzollernring 72, 50672 Cologne, District Court Cologne HRB 95366
Managing Board: Andreas Gauger, Dirk Valbert, Frank Hoberg, Stephan Martin
Chairman of the Board: Richard Seibt

PowerDNS.COM BV, Koninginnegracht 14L, 2514 AA Den Haag, The Netherlands
Managing Director: Robert Brandt, Maxim Letski
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