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From "Patrick Linskey" <>
Subject Re: uuid-string not generating unique ids
Date Wed, 25 Jul 2007 16:12:07 GMT

Based on a quick read, it looks like maybe the problem is I suspect that we should be changing that to
obtain another newTime inside the if block after incrementing the
sequence. However, I'm not an expert in this algorithm; does anyone
have a better grasp on it than do I?


On 7/25/07, Elias Torres <> wrote:
> Hi,
> First off, I want to say thank you for the hard work this community has
> put on this JPA implementation. I'm extremely eager in getting to know
> it better and hopefully put it to good use in some of the projects I'm
> currently working on at IBM. If all goes well, I'll be asking some of
> the harder questions later and possibly discuss new features not
> currently implemented.
> Now if you could please help me out with a small issue I'm having with
> uuid generation.
> @Entity
> public class Foo {
>   @Id
>   @GeneratedValue(strategy=GenerationType.AUTO, generator="uuid-string")
>   private String id;
> }
> }
> If I do one em.persist() it works just fine. However, if I do a a whole
> list of them, I get exceptions (duplicate). If I enable logging I can
> see they are all using the same id during INSERT. I stepped a bit
> through the code and noticed that uuid-string doesn't get generated
> while em.persist(), but much later while committing/flushing. I then
> looked a bit (just a bit) at the UUID generator code and noticed that
> the bytes are not changing much (maybe only the first two), but again,
> that was while debugging, so I'm assuming I have a supa-fast machine.
> Anybody running into the same problem? Any suggestions?
> -Elias

Patrick Linskey
202 669 5907

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