[Mongrel] Segmentation fault in Mongrel when run with --debug

Nathan Vack njvack at wisc.edu
Fri Dec 21 12:20:51 EST 2007

On Dec 21, 2007, at 9:38 AM, Scott Derrick wrote:

> I thinking rails just can't handle running periodically_call_remote  
> with
> an interval shorter than 1 second. eventually two calls are synced up
> and it deadlocks.  the faster I run periodically..  the sooner the
> deadlock.

Rails's code is probably OK in this case -- periodically_call_remote  
isn't inherently dangerous -- it just writes some javascript that  
periodically calls (via Prototype's Ajax.Request) a controller /  
action. If you use Firebug and make the same request in the console  
(without using p_c_r), you'll see the exact same problem after  
several (hundred?) requests.

The problem is probably (almost certainly) in either code you've  
written or in a library you're using. gdb will help you out here.

Really, though, this is offtopic for Mongrel's list -- either the  
Rails list or the Ruby list is a better match for these problems. The  
Rails IRC channel might also be useful. Or contact me off-list, and  
I'll help if I can...

> If I run lighttpd as a load balancer with cluster would that alleviate
> the problem?  If that is the problem?

Nope; it'll just put off the inevitable. You need to find and fix the  
deadlocking code. This can be challenging; race conditions are one of  
the least fun parts of programming.


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