Interesting; the first thing I tried when triaging this was to edit /etc/nsswitch.conf as follows:
# hosts: files mdns4_minimal [NOTFOUND=return] dns myhostname hosts: files dns ... to eliminate the possibility that it was multicast DNS causing the slowdown. But it appears I'm behind the times. ;-) (And didn't this only affect the .local domain?) Does this mean there are now two subsystems responsible for link-local address resolution? (avahi and systemd-resolved?) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1739672 Title: Regression in getaddrinfo(): calls block for much longer on Bionic (compared to Xenial) Status in glibc package in Ubuntu: Invalid Status in linux package in Ubuntu: Invalid Status in systemd package in Ubuntu: Confirmed Bug description: When testing MAAS on Bionic, we noticed sluggish performance that we could not immediately explain. After comparing the results from a run of the test suite on Xenial to a run on Bionic, we determined that the slowdowns had to do with DNS lookups. In particular, if MAAS attempts to resolve a hostname using getaddrinfo() and the call fails, on Xenial the negative result is returned in a fraction of a second. On Bionic, the negative result is returned in ~1.6 seconds, according to some measures. ### To run the test ### git clone https://github.com/mpontillo/test-getaddrinfo cd test-getaddrinfo make ### Results on Xenial ### $ time ./test not-a-real-hostname Trying to resolve: not-a-real-hostname getaddrinfo errno: Success getaddrinfo() return value: -2 (Name or service not known) real 0m0.015s user 0m0.000s sys 0m0.000s ### Results on Bionic ### $ time ./test not-a-real-hostname Trying to resolve: not-a-real-hostname getaddrinfo errno: Resource temporarily unavailable getaddrinfo() return value: -3 (Temporary failure in name resolution) real 0m1.609s user 0m0.004s sys 0m0.000s To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1739672/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
