[Zope-dev] Globally unique id's in Zope in a new way

[Jason Spisak]

Ross,

On my dual SMP PII 350 I still only create 48 objects using this short code
per second. 

<dtml-var standard_html_header>
<dtml-in "_.range(0,1000)">
 <dtml-with "ClientClass.createInObjectManager(_.getitem('unique_id',1),
REQUEST)">
 <dtml-var id>
 </dtml-with>
</dtml-in>
<dtml-var standard_html_footer>
 _.float works terrific.  I suppose a blend of the two techniques would
give a pretty solid id, even on very fast parallel machines, because they
would have to get the same random number from a large amount of
possiblities in under a millisecond. Thanks for both your help on this.


<dtml-var "_.str(_.float(ZopeTime())) +    
_.str(_.whrandom.randint(1,100000))">


All my best,


Ross Lazarus writes:

> ZopeTime() to float to string conversion works even better since you get
> milliseconds - there is always the risk that in an SMP processor
> environment, you JUST might get bitten, but that's also true of any
> hash algorithm - you're down to probabilities which are exceedingly
> small.
> 
> Of course, you could enclose your new id generating code (hash or float
> time) in some loop which checks to see if an object with that id
> exists, if it does, wait a small random time, and add a letter to the
> end of the string, retest and loop until it IS unique, then create the
> object. The time taken to do all that means you could be "safe" from
> multiple processors doing precisely the same thing at precisely the
> same time..
> 
> jason spisak <44-@hiretechs.com> wrote: 
> original article:http://www.egroups.com/group/zope/?start=25478
> > Zopsters,
> > 
> > numbers, employee numbers, etc...) so I don't like to use a counter
> for
> > ids.  The ZopeTime() to int to string conversion works unless you are
> > programatically creating multiple items in the same folder, and have a
> > descent processor.  I have derived the following bad hack from the
> code
> 
> 


Jason Spisak
CIO
HireTechs.com
6151 West Century Boulevard
Suite 900
Los Angeles, CA 90045
P. 310.665.3444
F. 310.665.3544

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