From: Bezan Kapadia <bezan99@...>
Date: 2009-02-16T05:55:43+09:00
Subject: Re: Got SystemStackError exception: stack level too deep

Ok .. Well I tested the Code again.

This Time the code errored out after 40 hrs with only the System Stack 
error.

Some things I have noted this time..
_________________________________________________
1)This is how my child process code that runs in the background looks 
like -

The code is precisely doing what Tony has indicated above that could be 
possibly triggering the Stack error exception.


#Main Program

def check_for_running_jobs
       begin

       # do a whole lot of work


       rescue Exception => e
      $mes_trace.error("In MES_monitor check_for_running_jobs : Got 
#{e.class} exception: #{e.message}")
      puts "Got #{e.class} exception: #{e.message}"
      $mes_trace.error(e.backtrace.join("\n"))
      puts e.backtrace.join("\n")

  end

end


def run_function

#this function internally calls tons of XYZ functions...
check_for_running_jobs
# there are rescue statements in various of these XYZ functions to trap 
exceptions....


sleep(60) #note it gets activated every 60 seconds

run_function
end

run_function

###################################
One thing I wanted to know that if I have an exception in some function 
(run_function and if I rescue that exception in the function 
(run_function or within other functions that this function calls) 
...does that restart execution of the entire program again (note am not 
doing anything like calling some other method or anything else except 
rescuing the error)....leading to stack error..
_______________________________________________

2) Just a Side Note - Am trying to run this background child process for 
days / may be even weeks something like a cron job that sleeps , wakes 
up, polls the status and goes to sleep.

Is it robust way to Run a detached child process in the background for 
weeks ...?
______________________________________________

3) Ok I have got hold of my backtrace if you folks want to take closer 
look...

I, [06:12:05#22059]  INFO -- : Sleeping for 2 Minutes
I, [06:13:05#22059]  INFO -- : Finished Sleeping for 2 Minutes
E, [06:13:05#22059] ERROR -- : In MES_monitor check_for_running_jobs : 
Got SystemStackError exception: stack level too deep
E, [06:13:05#22059] ERROR -- : 
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/monitor.rb:273:in 
`mon_check_owner'
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/monitor.rb:220:in `mon_exit'
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/monitor.rb:240:in `synchronize'
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/logger.rb:496:in `write'
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/logger.rb:326:in `add'
/usr/pkgs/ruby/1.8.5-p12/lib/ruby/1.8/logger.rb:374:in `info'
./MES_monitor.rb:90:in `check_for_running_jobs'
./MES_monitor.rb:78:in `times'
./MES_monitor.rb:78:in `check_for_running_jobs'
./MES_monitor.rb:70:in `each'
./MES_monitor.rb:70:in `check_for_running_jobs'
./MES_monitor.rb:272:in `run_function'
./MES_monitor.rb:281:in `run_function'
./MES_monitor.rb:283

_________________________________________________

4)

Jayce from what you suggested ...
#Main program

def run_function

#this function internally calls tons of XYZ functions...
check_for_running_jobs
# there are rescue statements in various of these XYZ functions to trap 
exceptions....

sleep(60) #note it gets activated every 60 seconds

run_function
end

begin
run_function

           rescue Exception => e
      $mes_trace.error("In MES_monitor check_for_running_jobs : Got 
#{e.class} exception: #{e.message}")
      puts "Got #{e.class} exception: #{e.message}"
      $mes_trace.error(e.backtrace.join("\n"))
      puts e.backtrace.join("\n")


end



Am going to fire test run with  the above change...Hopefully this will 
solve my problem ...
let me know if you folks suggest anything else....
__________________________________________
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