[erlang-questions] Erlang node memory consumption grows to 18GB in few seconds

[Raimo Niskanen]

On Sun, Apr 15, 2018 at 06:47:19PM +0530, Chaitanya Chalasani wrote:
> Thank you for that suggestion, Danil.
> 
> However, removing the io:format alone didn’t solve the problem. I had to change the send function too.
> 
> From:
> 
> send(Data) ->
>  ?MODULE ! {send, Data}. 
> 
> To:
> 
> send(Data) ->
>   ?MODULE ! {send, Data},
>   ok.
> 
> Does the shell also use io:format to show the function return value?

The return value from all shell commands are saved in the shell history.
/ Raimo



> 
> > On 15-Apr-2018, at 18:40, Danil Zagoskin <z@REDACTED> wrote:
> > 
> > Never use io:format("~p") on large data.
> > Simple solution is to limit depth: io:format("~P~n", [Data, 30])
> > 
> > On Sat, Apr 14, 2018 at 12:55 PM, Chaitanya Chalasani <cchalasani@REDACTED> wrote:
> >> Hi,
> >> 
> >> I see the memory consumption of an erlang node grows exponentially and
> >> quickly when I was sending binary data of about 700 MB from shell to a
> >> simple erlang listener process and the shell process is stuck.
> >> 
> >> -module(strange).
> >> -export([start/0, listener/0, send/1, stop/0]).
> >> 
> >> start() ->
> >>  register(?MODULE, spawn(?MODULE, listener, [])).
> >> 
> >> listener() ->
> >>  receive
> >>    {send, Data} ->
> >>      io:format("Received Data ~p ~n", [Data]),
> >>      listener();
> >>    stop ->
> >>      io:format("Stopping listener ~n")
> >>  end.
> >> 
> >> send(Data) ->
> >>  ?MODULE ! {send, Data}.
> >> 
> >> stop() ->
> >>  ?MODULE ! stop.
> >> 
> >> $ uname -a
> >> Darwin Chaitanyas-MacBook-Pro.local 17.5.0 Darwin Kernel Version 17.5.0: Mon
> >> Mar  5 22:24:32 PST 2018; root:xnu-4570.51.1~1/RELEASE_X86_64 x86_64
> >> 
> >> $ erl
> >> Erlang/OTP 20 [erts-9.3] [source] [64-bit] [smp:8:8] [ds:8:8:10]
> >> [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
> >> 
> >> Eshell V9.3  (abort with ^G)
> >> 1> c(strange).
> >> {ok,strange}
> >> 2> {ok, Data} = file:read_file("centos.iso").
> >> {ok,<<51,237,144,144,144,144,144,144,144,144,144,144,144,
> >>      144,144,144,144,144,144,144,144,144,144,144,144,
> >>      144,144,...>>}
> >> 3> strange:start().
> >> true
> >> 4> strange:send(Data).
> >> 
> >> BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
> >>       (v)ersion (k)ill (D)b-tables (d)istribution
> >> 
> >> The observer says -
> >> <0.53.0> group:server/3 93980000 17957208520 1 erlang:integer_to_list/1
> >> 
> >> The Mac activity monitor shows Erlang consuming 18GB of RAM.
> >> 
> >> Kindly, help me understand what is happening.
> >> 
> >> /Chaitanya
> >> 
> >> _______________________________________________
> >> erlang-questions mailing list
> >> erlang-questions@REDACTED
> >> http://erlang.org/mailman/listinfo/erlang-questions
> >> 
> > 
> > 
> > 
> > -- 
> > Danil Zagoskin | z@REDACTED
> 
> _______________________________________________
> erlang-questions mailing list
> erlang-questions@REDACTED
> http://erlang.org/mailman/listinfo/erlang-questions

-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB