From: George Ogata <g_ogata@...>
Date: 2004-07-03T07:37:47+09:00
Subject: Re: slow method searching?

David Garamond <lists@zara.6.isreserved.com> writes:

> Why does it take longer and longer for Ruby to throw NoMethodError for 
> large arrays? What is going on here? This happens with hash too.

Ok, my turn to guess... :)


g@crash:~$ time ruby -e 'a=(1..2000000).to_a; a.classx'
-e:1: undefined method `classx' for #<Array:0x401cfebc> (NoMethodError)

real    0m6.100s
user    0m5.897s
sys     0m0.104s
g@crash:~$ time ruby -e 'a=(1..2000000).to_a; begin a.classx; rescue NoMethodError; end'

real    0m0.458s
user    0m0.449s
sys     0m0.008s


I'm guessing the time is spent "stringifying" the array when
outputting exception message.  Note that for shorter arrays, the array
is actually printed.


g@crash:~$ time ruby -e 'a=(1..2).to_a; a.classx'
-e:1: undefined method `classx' for [1, 2]:Array (NoMethodError)

real    0m0.005s
user    0m0.003s
sys     0m0.001s


I don't know what the criteria is for when to print the object and
when not to; perhaps it's based on the length of the string in which
case the large array is stringified only to have the string thrown
away.