<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">The timer module is basically a <i>gen_server</i> that is using timeouts to invoke a timer and an <i>ordered_set </i>ETS to store the timers<div>The ordered_set is probably the cause of the memory issues you are referring to, and the gen_server/timeout implementation is, well, not exactly the most scalable way to do this...</div><div><br></div><div>Cheers<br><div>
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<br><div><div>On Sep 21, 2012, at 7:25 PM, Michael Truog wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On 09/21/2012 03:15 PM, <a href="mailto:freza@circlewave.net">freza@circlewave.net</a> wrote:<br><blockquote type="cite"><blockquote type="cite">3. Is spawning a lot of send_after's or timers a dangerous idea? In case of<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">using timer module, we'll just lose some started timers due to port<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">restart. But something tells me that crash of erlang internal timers is a<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">somewhat more dangerous thing that might even crash the VM.<br></blockquote></blockquote><blockquote type="cite">Not sure I understand you here.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">These timers are a facility built directly into ERTS. If there were a<br></blockquote><blockquote type="cite">bug somewhere in the implementation, that could be as horribly nasty<br></blockquote><blockquote type="cite">as any other bug in ERTS. Other than that, they are dead pieces of<br></blockquote><blockquote type="cite">data interpreted in some conventional way by a bunch of C code, so<br></blockquote><blockquote type="cite">as such they can't really "crash" in any obvious meaning of the<br></blockquote><blockquote type="cite">word.<br></blockquote><br>I remember reading about problems using the timer module with a large number of timers because of excessive memory consumption, such that erlang:send_after/3 or erlang:start_timer/3 is generally the preferred approach. I don't have a link to the mailing list message(s) for instances of that problem, but I assume it is still an issue today, because of extra storage used by the timer module.<br><br>_______________________________________________<br>erlang-questions mailing list<br><a href="mailto:erlang-questions@erlang.org">erlang-questions@erlang.org</a><br>http://erlang.org/mailman/listinfo/erlang-questions<br></div></blockquote></div><br></div></body></html>