From: Kent Sibilev <ksruby@...>
Date: 2009-03-31T00:06:00+09:00
Subject: Re: Symbols garbage collector in Ruby1.9, fixed?

On Mon, Mar 30, 2009 at 8:48 AM, James Gray <james@grayproductions.net> wrote:
> On Mar 30, 2009, at 7:16 AM, Brian Candler wrote:
>
>> Iņaki Baz Castillo wrote:
>>>
>>> I could use strings as keys instead of symbols, but I've checked that
>>> getting a Hash entry is ~25% faster using Symbols.
>>>
>>> The problem is that I could receive custom headers so for each one a
>>> new Symbol would be created. An attacker could send lots of custom
>>> headers to fill the server memory and cause a denial of service.
>>>
>>> Perhaps this is solved in Ruby 1.9? any suggestion on it? Thanks a lot.
>>
>> It's not "solved" in 1.9, because this is intentional and necessary
>> behaviour.
>
> Dave Thomas seems to have thought this was going away:
>
> http://pragdave.blogs.pragprog.com/pragdave/2008/05/ruby-symbols-in.html
>
> James Edward Gray II
>

Unfortunately, symbols are still not garbage-collected at the moment.
It seems that the only difference comparing to 1.8 is that symbols are
backed by real frozen string objects instead of arrays of chars.

-- 
Kent