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Date: Fri, 18 Oct 2013 19:50:45 -0400
Message-ID: 
 <CAPxJ8xtrKbZE4j_0ebPCDfxScjzAviGnDuNJWjX9OzqkDrr+YQ@mail.gmail.com>
Subject: Re: UID performance
From: Mark Kessler <kesslerconsulting@gmail.com>
To: "Dev@Flex" <dev@flex.apache.org>
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I ran the swf file from your link and I got these...


On Fri, Oct 18, 2013 at 7:45 PM, Maurice Amsellem <
maurice.amsellem@systar.com> wrote:

> I have posted FB project with the source s + compiled SWF.
>
> https://dl.dropboxusercontent.com/u/12169005/ApacheFlex/TestUIDPerf.fxp
> https://dl.dropboxusercontent.com/u/12169005/ApacheFlex/TestUIDPerf.swf
>
> Algorithm 1=3D Original
> Algorithm 2 =3D using Array.join() and other optimizations by JMcLean
> Algo 3:  using single static byteArray (Maurice)
>
> These are the results I get for 100,000 iterations:
>
> Original: 2.74s
> V2:  2.5s
> V3:  1.70s
>
> Please can you test on your side as well...
>
> Maurice
>
> -----Message d'origine-----
> De : Maurice Amsellem [mailto:maurice.amsellem@systar.com]
> Envoy=E9 : samedi 19 octobre 2013 00:56
> =C0 : dev@flex.apache.org
> Objet : RE: UID performance
>
> I have used a static ByteArray as suggested: much better.
> Thanks for the suggestion.
>
>
> -----Message d'origine-----
> De : Maurice Amsellem [mailto:maurice.amsellem@systar.com]
> Envoy=E9 : samedi 19 octobre 2013 00:49
> =C0 : dev@flex.apache.org
> Objet : RE: UID performance
>
> Sure, I will do that.
>
> I will  also post the source so that you can recompile at your convenienc=
e.
>
> Maurice
>
>
> -----Message d'origine-----
> De : Alex Harui [mailto:aharui@adobe.com] Envoy=E9 : samedi 19 octobre 20=
13
> 00:13 =C0 : dev@flex.apache.org Objet : Re: UID performance
>
> I'm a bit surprised that ByteArray.writeByte is faster but maybe
> Array.join isn't that fast.  I would also like to see a test of a single
> static bytearray and resetting it and/or overwriting the old bytes.
>
> Maybe if you put a SWF with various algorithms in your people.a.o folder
> folks can hit it and make sure we all get the same results and then we'll
> know which algorithm to check in.
>
> Thanks for this idea as well.
>
> -Alex
>
> On 10/18/13 3:05 PM, "Maurice Amsellem" <maurice.amsellem@systar.com>
> wrote:
>
> >Any answer ?
> >
> >-----Message d'origine-----
> >De : Maurice Amsellem [mailto:maurice.amsellem@systar.com]
> >Envoy=E9 : vendredi 18 octobre 2013 14:39 =C0 : dev@flex.apache.org Obje=
t :
> >RE: UID performance
> >
> >Hi,
> >
> >I shouldn't have mixed the two options, because it's confusing.
> >
> >Actually, V3 option generates uppercase, exactly as the current UUID,
> >and it's 2x faster.
> >So let's forget about V4...
> >
> >Here is the code:
> >
> >    private static const HEX_CHARS:String =3D "0123456789ABCDEF";
> >    private static const DASH:int =3D 45;  // "-"
> >
> >public static function createUID():String
> >    {
> >        var ba:ByteArray =3D new ByteArray();
> >        var i:int;
> >        var j:int;
> >
> >        for (i =3D 0; i < 8; i++) {
> >            ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16));
> >       }
> >
> >        for (i =3D 0; i < 3; i++)
> >        {
> >            ba.writeByte(DASH);
> >            for (j =3D 0; j < 4; j++)
> >            {
> >                ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16));
> >            }
> >        }
> >
> >        ba.writeByte(DASH);
> >
> >        var time:Number =3D new Date().getTime();
> >
> >        var timeString:String =3D ("0000000" +
> >time.toString(16).toUpperCase()).substr(-8);
> >        ba.writeUTFBytes(timeString);
> >
> >        for (i =3D 0; i < 4; i++)
> >        {
> >            ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16));
> >        }
> >
> >        return ba.toString();
> >    }
> >
> >-----Message d'origine-----
> >De : Justin Mclean [mailto:justin@classsoftware.com] Envoy=E9 : vendredi
> >18 octobre 2013 14:34 =C0 : dev@flex.apache.org Objet : Re: UID
> >performance
> >
> >Hi,
> >
> >> V3: generates the random hex bytes one by one, and writes them to the
> >> BA
> >> V4: generates 4 or 8 random bytes in one shot, and writes them to the
> >> BA  (hexa in lowercase, to avoid call toUppercase() )
> >Probably best not too fiddle too much with the UID construction. While
> >I can't think of any major issues it would cause there could be subtle
> >issues due to seeding of random numbers and the like.
> >
> >> I don't know if this is acceptable (are we breaking some code if we
> >>use lowercase instead of uppercase).
> >
> >Again can't think of any issues but probably safer if we kept it upper
> >case.
> >
> >Go ahead and post the code it could be interesting/useful to someone.
> >
> >Thanks,
> >Justin
>
>

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