From: "Hal E. Fulton" <hal9000@...>
Date: 2002-01-16T03:09:46+09:00
Subject: Re: memory usage question

----- Original Message -----
From: "Mark Hahn" <mchahn@facelink.com>
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>
Sent: Tuesday, January 15, 2002 11:37 AM
Subject: memory usage question


> I need to write a script that will use a hash with 4 million strings of 16
> chars each.  As a test I wrote this quick script:
>
>   h = {}; s = 'aaaaaaaaaaaaaaaa'
>   for i in 1..4_000_000
>     h[i] = (s = s.succ)
>   end
>
> This ran relatively fast, but it consumed 265 megs of windows memory and
> failed with out of memory error at around 3 million elements.
>
> Why did Ruby fail at 265 megs and is there another way for me to do this?

Four million strings, eh?  :)

<oldtimer_rant>
Buncha young kids wanna allocate data structures with four million
items... in my day, we had 64K of RAM and part of that was the OS
and the runtime. The compiler wouldn't all fit in memory at once. It
was swapped out to this clunky external Shugart floppy disk drive
that would walk across the table if you didn't tape it down. It made a
noise like a boa constrictor gagging on a weasel. And the compiler
couldn't handle arrays bigger than a thousand elements.
And we LIKED IT...
</oldtimer_rant>

But seriously...  :)

Even today when RAM approaches a gigabyte in daily life (and your PC
may have a terabyte drive soon), memory ain't always the way to go.

Eventually you should consider using a database or something instead.
If you want something that will have a low impact on your code, try the
dbm interface. Very easy, not as much overhead as a "real" database.

There's also gdbm and maybe one or two other flavors. Not sure what
the differences are. Last time I tried, gdbm worked better for me on
Windows.

I think it's part of the standard distribution.

Hope this helps.

Hal