From: Matt Armstrong <matt@...>
Date: 2002-01-16T04:14:51+09:00
Subject: Re: memory usage question

Phil Tomson <ptkwt@aracnet.com> writes:

> On Tue, 15 Jan 2002, Matt Armstrong wrote:
>
>> ptkwt@shell1.aracnet.com (Phil Tomson) writes:
>>
>> > In article <CEENJIKJHPPGICBNAFMICEJKDEAA.mchahn@facelink.com>,
>> > Mark Hahn <mchahn@facelink.com> wrote:
>> >>
>> >>> you should consider using a database
>> >>
>> >>Doing 200 million lookups in a db would take way too long for my
>> >>script.  If there is no other work-around than using a DB, then I'll
>> >>have to go back to Java, which can handle this kind of memory usage.
>> >>I'm dissapointed that in one of the first quick scripts I went to
>> >>Ruby for, Ruby couldn't do the job.
>> >
>> > How does java acheive this feat?
>> > (or how do you do it in java?)
>>
>> 4 million 16 character strings is only 64 megs.
>
> They're not wide characters in java?
>
> So you're saying that Ruby strings take up more space? (probably,
> since doesn't ruby use wide chars?)
>
> What do these 16 character strings represent?

You're right, think Java does us 16 bit Unicode chars.  Ruby doesn't.
It uses UTF-8 or SJIS, etc.  These all use one byte for an ASCII
character and multiple byte encodings for others.


>> Even if the overhead of a String object itself and the entry in the
>> hash table is 4 times that, you're still only at about 300 megs.
>> On a machine with 4 gigs of RAM, that should be possible.
>
> Yes, but I think that's a lot more available RAM than you mentioned
> in your original post.  From what you said earlier if you 4gigs of
> RAM then the Ruby version should work without any problem (am I
> missing something?)

Exactly, but the original poster says it doesn't work -- that is the
whole question.


-- 
matt