From: Thomas Hurst <tom.hurst@...>
Date: 2008-01-15T02:03:09+09:00
Subject: Re: 1.9 significantly slower than 1.8 on Mac

* Derek Chesterfield (groups@dezuk.com) wrote:

> On 13 Jan 2008, at 02:15, Marcin Miel??y??ski wrote:
> 
>> Ruby 1.9 uses Oniguruma which is an encoding agnostic engine.
> 
> So Ruby 1.9.0's Regexp is slower than 1.8's?

In some cases, probably; it does quite a bit more, not just in encoding
support, but more regexp features.  e.g, from a quick glance through
http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt :

 Zero-width lookbehind assertions (/(?<=foo)bar/ =~ 'foobar' # $& => "bar")
 
 Named captures (/(?<foo>bar))/ =~ 'foobar' # $~[:foo] => "bar")
 
 Fancier backreferences (/(?<foo>foo|bar)\k<foo>/ =~ "foobar" # => nil,
                         .. =~ 'foofoo' # $& => "foofoo")

 The ability to call subexpressions
      (/(?<foo>foo|bar)\g<foo>/ =~ "foobar" # $& => "foobar", $2 => bar)

You might consider installing a separate Ruby 1.8 with Oniguruma patched
in, or installing the Oniguruma gem, so you can test the performance
without bringing YARV into the equation.

> Damn - All my Ruby scripts make extensive use of Regexp.  Will this
> always be the case, or might 1.9.1 be worth me upgrading to?

Oniguruma's pretty mature by now, I wouldn't expect the general
performance profile to change that significantly, although the recent
port to Java might trigger some changes.

I wouldn't be too worried; I've used it for well over a year and not
really noticed any significant performance issues.  In the worst case,
alternative engines could always be supported through extensions.

-- 
Thomas 'Freaky' Hurst
    http://hur.st/