From: Horacio Sanson <hsanson@...>
Date: 2006-01-19T19:56:10+09:00
Subject: Memory Leak (again)


There is a little memory leak in my script I am not able to spot. I have tried 
everything I found about detecting leaks but no luck.

I first tried all the recomendations found here

http://theexciter.com/articles/finding-leaking-ruby-objects?commented=1#c000092

I can see the number of objects but the total number of objects does not 
increment indefinitely but the script keeps consuming memory.

I tried this code:

##################################33
Entry = Struct.new( "MEntry", :c, :mem )
class MEntry; def to_s() "#{c} : #{mem}"; end; end

GroupEntry = Struct.new( "GroupEntry", :c, :mem, :total )
class GroupEntry; def to_s() "#{c} x#{total}(#{mem})"; end; end

def profile_mem
    groups = {}
    ObjectSpace.each_object { |x|
            e = nil
            begin
                e = MEntry.new( x.class, Marshal::dump(x).size )
            rescue TypeError # undumpable
                e = MEntry.new( x.class, 0 )
            end
            if groups.has_key? e.c
                groups[e.c].mem += e.mem
                groups[e.c].total += 1
            else
                groups[e.c] = GroupEntry.new( e.c, e.mem, 1 )
            end
    }
    File.open( "mem_log", "a+" ) { |file|
        total = 0
        groups.to_a.sort_by { |e| e[1].mem }.each { |e|
            file << "#{e[1]} ";
            total += e[1].mem
        }
        file << "TOTAL == #{total}"
        file << "\n"
    }
end


This code gives a list of all objects in ObjectSpace and their memory usage. 
Also I log the total memory usage. 

The log indicates that my scripts uses between 3 to 4 megs of memory 
constantly, that is, it fluctuates between these values but the windows 
manager indicates that the memory increase all the time and never goes down.

Running the script for a day consumes all 2G ram of my machine and causes the 
script to bail out.

So are there any other tips on how to detect memory leaks??  Ruby Memory 
Validator is only available to accepted beta testers so is not an option for 
me.

I use Windows XP pro with the One-Click Ruby installer (1.8.2) and 
ActiveRecord (1.13.2).

Any ideas are welcome...

regards,
Horacio