From: Robert Klemme <shortcutter@...>
Date: 2012-08-31T22:56:17+09:00
Subject: Re: Array Size in Ruby

On Fri, Aug 31, 2012 at 2:57 PM, Sigurd <cu9ypd@gmail.com> wrote:
> If you use ruby 1.9.2 or later you can try following approach:
> require 'objspace'
>
> ObjectSpace.memsize_of(array).tap do |size|
>         array.each do |el|
>                 size += ObjectSpace.memsize_of(el)
>         end
> end

That does not work since tap will return the result of memsize_of(array) only.

irb(main):003:0> 123.tap {|s| s + 999}
=> 123
irb(main):004:0> 123.tap {|s| s += 999}
=> 123

> That you'll give you size of memory taken. But that does not take into account the size of ruby RObject internal struct that is referencing every single ruby object.  It's size depends on 32/64 bit platform and packing options. My guess that it's around 128 bytes.

It also does not take into account memory taken by all referenced
objects since you descend one level only.  You would need a DFS of BFS
to properly account for all levels.

Kind regards

robert


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