# Newbie question regarding memory leak

**URL:** <https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545>\
**Category:** Ruby\
**Created:** [March 11, 2008, 7:33am UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545 "2008-03-11T07:33:30Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![learningruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/6bbea6/32.png) [@learningruby](https://www.ruby-forum.com/u/learningruby)\
**Post date:** [March 11, 2008, 7:33am UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545/1 "2008-03-11T07:33:30Z")

</div>

Hi, Recently, I have written a ruby program for web-scraping. But its a  
bit slow and consumes enormous memory due to a possible memory leak. I  
am very new to these memory leak issues. Please find my code in the  
attachment.

Can anyone patiently go through my code and figure out where the  
possible mem leak occurs? Any help/suggestion greatly appreciated…

thanks & regards,  
Venkat B.

---

<div class="post-metadata">

**Author:** ![learningruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/6bbea6/32.png) [@learningruby](https://www.ruby-forum.com/u/learningruby)\
**Post date:** [March 11, 2008, 12:24pm UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545/2 "2008-03-11T12:24:05Z")

</div>

On Tue, Mar 11, 2008 at 1:33 AM, Venkat B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Attachments:  
> [http://www.ruby-forum.com/attachment/1561/test4.rb](http://www.ruby-forum.com/attachment/1561/test4.rb)
> 
> –  
> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).

Where do you think your memory leak is? (Also, why don’t you think  
Ruby’s garbage collecting is handling it? Maybe you have references  
to things you’re not using anymore?)

– Ben (aka divokz)

---

<div class="post-metadata">

**Author:** ![learningruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/6bbea6/32.png) [@learningruby](https://www.ruby-forum.com/u/learningruby)\
**Post date:** [March 11, 2008, 1:51pm UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545/3 "2008-03-11T13:51:58Z")

</div>

Ben Oakes wrote:

> Where do you think your memory leak is? (Also, why don’t you think  
> Ruby’s garbage collecting is handling it? Maybe you have references  
> to things you’re not using anymore?)

I have assigned the useless object references to nil. You can observe, I  
assigned

page = nil  
page\_links = nil  
doc = nil  
file\_name = nil at some point of the program, where I no longer needed  
them. Doesn’t assigning a ref to nil, completely free its object memory?  
Isn’t nil an empty object? Does nil also claims memory? I am very sorry  
if my questions doesn’t make any sense !!!

---

<div class="post-metadata">

**Author:** ![learningruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/6bbea6/32.png) [@learningruby](https://www.ruby-forum.com/u/learningruby)\
**Post date:** [March 19, 2008, 3:30pm UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545/4 "2008-03-19T15:30:12Z")

</div>

On Tue, Mar 11, 2008 at 7:51 AM, Venkat B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> page\_links = nil

I haven’t had much time to review the code you’ve posted, but  
regarding your questions here, nil _does_ take up memory, however,  
there is only _one_ instance of nil (or NilClass, rather), if I  
remember correctly. Whenever you use “nil,” you are using the  
reference to that class. (That is, every nil points to the same  
place.) If you believe that your objects are still resident after  
garbage collecting, there’s a chance that you still have references to  
them somewhere in memory. (For example, you may set a variable that  
once held an array to nil, but then if that array had references to  
other objects, there would still be a reference count above 0, so the  
objects would stick around. I’m not sure if that example would hold  
true, but I believe that’s what the general idea is.)

I hope this helps,

– Ben

---

<div class="post-metadata">

**Author:** ![learningruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/6bbea6/32.png) [@learningruby](https://www.ruby-forum.com/u/learningruby)\
**Post date:** [March 21, 2008, 6:43am UTC](https://www.ruby-forum.com/t/newbie-question-regarding-memory-leak/131545/5 "2008-03-21T06:43:25Z")

</div>

Atlast I figured it out. Rather than declaring @agent as an instance  
variable, i tried declaring it as a local variable and that does the  
trick. Previously it used to eat up 400-500 MB of memory but now, it  
uses a max of 15 MB.

I modified my code from

def initialize  
@agent = WWW::Mechanize.new  
end

def fetch\_links(start, finish, count)  
page = WWW::Mechanize::Page  
…  
…  
end

to look like below

def initialize

end

def fetch\_links(start, finish, count)  
agent = WWW::Mechanize.new  
page = WWW::Mechanize::Page  
end

Any interpretations from this?