[erlang-questions] trading systems

Jayson Vantuyl kagato@REDACTED
Thu Oct 1 22:36:54 CEST 2009

> The difficulty with Erlang is tracking the state of all the message  
> queues at any given moment and just plain figuring out what's going  
> on among all the different processes. I have resorted to various  
> tricks apart from tracing, e.g. putting stuff into the process  
> dictionary at various stages of process life for ease of fetching  
> via process_info.
Are you using vanilla tracing, sequential tracing, or both?  Yes, the  
mailboxes are the number one headache for me.

You can always get at the message queue with  
erlang:process_info(self(),messages).  I have a check in most of my  
servers that, when I'm debugging, will dump the message queue to disk  
if it gets over a certain size.  Helps me track down places that need  
to be synchronized to prevent run-ahead.

>> That said, Erlang certainly takes a specific mindset to optimize.   
>> Are these built with Distributed Erlang?
> Distributed Erlang indeed. Very distributed. Check the recent  
> netsplit thread for some of the weirdness. Go back to the "Ultimate  
> Erlang Challenge" for more.
Yeah.  Since distribution modules are C, I doubt it's going to get  
fixed any time soon though.  :(

Jayson Vantuyl

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