[erlang-questions] On selective receive (Re: eep: multiple patterns)

[Massimo Cesaro]

2008/6/6 Robert Virding <rvirding@REDACTED>:

>
> I have a serious question which I ask out of ignorance. I know that really
> long message queues are possible in the existing language, it is easy to
> write a program to show this, but do they occur in real applications? Or is
> this theoretical worry? And if they do occur are they something which is
> property of the problem which can't easily be avoided or are they the result
> of some error in the logic or coding which shows up in message queue length?
>
> Robert
>

In a very complex TLC application that we released on field a couple of
years ago, and which was soak tested in our labs, we experienced massive
message queued do to disk I/O. The system was performing quite well for most
of the time, but on rare occasions, writing to a sequential file on the file
system provoked a buildup of messages on a couple of processes that in turn
slowed everything to a crawl. So this is not a theoretical worry, and in our
case it was not an error in the coding logic. We fixed it by completely
bypassing the writing to the file system step in favor of a different
approach involving a RAM based configuration mechanism.

Massimo
-- 
- Is there anything I can do?
- Computer says "no".
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