# "Out of memory" error in active\_record\_runtime()

**URL:** <https://www.ruby-forum.com/t/out-of-memory-error-in-active-record-runtime/121803>\
**Category:** Rails\
**Created:** [December 1, 2007, 1:14am UTC](https://www.ruby-forum.com/t/out-of-memory-error-in-active-record-runtime/121803 "2007-12-01T01:14:56Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![tirsen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f475e1/32.png) [@tirsen](https://www.ruby-forum.com/u/tirsen)\
**Post date:** [December 1, 2007, 1:14am UTC](https://www.ruby-forum.com/t/out-of-memory-error-in-active-record-runtime/121803/1 "2007-12-01T01:14:56Z")

</div>

I’ve come across an apparent bug in Rail 1.2.6 while going through the  
Depot sample code in “Agile Web D…”. I’ve done some  
searches, and couldn’t find anything referencing this problem.

I’ve patched around it, but not sure if what I have is a real fix, and  
have never submitted a bug fix to the Rails community before, so thought  
I’d start here.

Not sure if this is actually a bug in Rails or if it lives deeper in  
Ruby. It should be easy to reproduce, since it manifests itself in  
Depot.

I’d previously run through all the the Depot code, and written a Rails  
application using Rails 1.1.9. I wanted to dust-off my Rails and update  
the app, so I first updated to Rails 2.2.6 I am running Ruby 1.8.5  
(2007-09-24 patchlevel 114) [x86\_64-linux] which is the current Ruby in  
the Fedora Core 6 repository.

Note that I didn’t try to upgrade my old Depot application, as my goal  
was to review the basics. I started from scratch, so no issues with  
incompatibility of previously-generated code.

The bug shows itself in Iteration C4, upon pressing the “Clear Cart”  
button:

* * *

NoMemoryError in StoreController#empty\_cart

negative allocation size (or too big)

RAILS\_ROOT: ./script/…/config/…  
Application Trace | Framework Trace | Full Trace

## /usr/lib64/ruby/gems/1.8/gems/actionpack-1.13.6/lib/action\_controller/benchmarking.rb:86:in `sprintf' /usr/lib64/ruby/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/benchmarking.rb:86:in`active\_record\_runtime’

Here’s the function that is failing, along with my fix. The  
commented-out line is the original code - the next line is my fix:

```
  def active_record_runtime(runtime)
    db_runtime = ActiveRecord::Base.connection.reset_runtime
    db_runtime += @db_rt_before_render if @db_rt_before_render
    db_runtime += @db_rt_after_render if @db_rt_after_render
    db_percentage = (db_runtime * 100) / runtime
    #" | DB: #{sprintf("%.5f", db_runtime)} (#{sprintf("%d",

```

db\_percentage)}%)"  
" DB: #{sprintf("%.5f", db\_runtime)} (#{sprintf("%.f",  
db\_percentage)}%)"  
end  
end  
end

The sprintf with the %d format specification is throwing this error.  
Replacing it with a %.f works-around the problem, but, as I said above,  
I suspect that I might just be wallpapering-over some deeper problem in  
sprintf.

With the patch in place, I discovered that in this case, the value of  
db\_runtime is 0.0, and thus db\_percentage as well is 0.0. Prior to this  
point in Depot, I apparently hadn’t encountered another 0.0 value for  
db\_runtime. Of course, this is because there’s no database access - it’s  
just the first place working through the example that a page does no  
database access.

So, I boiled this down to an incredibly-simple test case:

[jon@colossus ~]$ irb  
irb(main):001:0\> sprintf("%d", 0.0)  
(irb):1:in `sprintf': negative allocation size (or too big) (NoMemoryError) from (irb):1:in`irb\_binding’  
from /usr/lib/ruby/1.8/irb/workspace.rb:52:in `irb\_binding’  
from /usr/lib/ruby/1.8/irb/workspace.rb:52

Now, I’m not sure if this is valid behavior or not. Is %d not supposed  
to be used on floating-point values? It seems to fail only for a  
floating-point value of 0.0. An integer 0 is fine.

---

<div class="post-metadata">

**Author:** ![tirsen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f475e1/32.png) [@tirsen](https://www.ruby-forum.com/u/tirsen)\
**Post date:** [December 1, 2007, 8:29am UTC](https://www.ruby-forum.com/t/out-of-memory-error-in-active-record-runtime/121803/2 "2007-12-01T08:29:39Z")

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Jon Tara wrote:

> I’d previously run through all the the Depot code, and written a Rails  
> application using Rails 1.1.9. I wanted to dust-off my Rails and update  
> the app, so I first updated to Rails 2.2.6 I am running Ruby 1.8.5  
> (2007-09-24 patchlevel 114) [x86\_64-linux] which is the current Ruby in  
> the Fedora Core 6 repository.  
> …  
> NoMemoryError in StoreController#empty\_cart
> 
> negative allocation size (or too big)

[http://groups.google.com/group/rubyonrails-talk/browse\_thread/thread/da3d6c49bdaf984c](http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/da3d6c49bdaf984c)

–  
We develop, watch us RoR, in numbers too big to ignore.