[erlang-questions] Number of dns resolvers

Yuri Ginsburg <>
Tue Mar 2 23:30:29 CET 2010


That's the line:
{resolv_conf, "/etc/resolv.conf"}

that causes syntax error on R12... but is OK in R13..

--
YG10 Yuri Ginsburg

On Tue, Mar 2, 2010 at 1:20 PM, Konstantin Sorokin <> wrote:

> On Wed, Mar 3, 2010 at 12:18 AM, Geoff Cant <> wrote:
> > Konstantin Sorokin <> writes:
> >
> >> On Tue, Mar 2, 2010 at 12:24 AM, Geoff Cant <> wrote:
> >>> Konstantin Sorokin <> writes:
> >>>
> >>>> Hello!
> >>>>
> >>>> How do I control number of dns resolvers in Erlang VM ? As far as I
> >>>> can see by default there are only 4 DNS resolvers (inet_gethost port
> >>>> processes) and if my app performs massive DNS lookups in many parallel
> >>>> processes then I probably should increase that number, right ? Are
> >>>> there any other parameters that I can tweak to increase DNS lookup
> >>>> speed ?
> >>>
> >>> There seems to be an undocumented? kernel configuration parameter
> >>> 'gethost_poolsize'::non_neg_integer() that specifies this.
> >>>
> >>> As an alternative to using the c resolver (the 'native' resolver) you
> >>> could use OTP's erlang DNS client - the 'dns' resolver.
> >>>
> >>> Specifying "{lookup, [dns]}." in your inetrc should do that (and erl
> >>> -kernel inetrc '"/some/path/inetrc"'). I don't think there's any
> >>> concurrency limit on it except the number of udp sockets you can open.
> >>>
> >>
> >> I tried to use your tip, but without success. Config file I wrote
> >> looks like this:
> >>
> >> {resolv_conf, "/etc/resolv.conf"}.
> >> {file, hosts, "/etc/hosts"}.
> >> {edns, 0}.
> >> {cache_size, 0}.
> >> {lookup, [dns]}.
> >>
> >> and was almost copy-pasted from this page:
> >> http://ftp.sunet.se/pub/lang/erlang/doc/apps/erts/inet_cfg.html (7.3
> >> User Configuration Example). Nevertheless,
> >> when I tried to use it with an Erlang shell, I've got following weird
> >> error message:
> >>
> >> $ erl  -kernel inetrc "'/home/kvs/.erl_inetrc'"
> >> {error_logger,{{2010,3,2},{23,40,21}},"inet_config: syntax error in
> >> ~s~n",['/home/kvs/.erl_inetrc']}
> >> Erlang (BEAM) emulator version 5.6.5 [source] [64-bit] [smp:2]
> >> [async-threads:0] [hipe] [kernel-poll:false]
> >
> > You're using Erlang/OTP R12B5, the edns option was only introduced in
> > R13 I think. If you drop the 'edns' option it should work in R12.
> >
>
> No, it doesn't :(
>
> --
> Konstantin Sorokin
>
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