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From "Patrick Linskey" <plins...@gmail.com>
Subject Re: uuid-string not generating unique ids
Date Wed, 25 Jul 2007 19:02:51 GMT
Great! What type of hardware are you running on, btw? We were already
doing some testing in a pretty tight loop, but maybe Hotspot was being
clever and optimizing it away.

-Patrick

On 7/25/07, Elias Torres <elias@torrez.us> wrote:
> FYI, the patch worked.
>
> -Elias
>
> Patrick Linskey wrote:
> > There have been a lot of changes since then, but things should be
> > pretty compatible.
> >
> > If you've got a good test suite, I'd recommend switching to trunk and
> > seeing what happens.
> >
> > -Patrick
> >
> > On 7/25/07, Elias Torres <elias@torrez.us> wrote:
> >>
> >> Thank you Patrick and Mark. I'm using 0.9.7, so I'm either patching it
> >> or switching to trunk. Do you think it'd be safe (for an agile
> >> development group) to switch to trunk from 0.9.7 or were there many big
> >> changes since then?
> >>
> >> Anyways, thanks again. I'll ask a couple of other things later.
> >>
> >> -Elias
> >>
> >> Patrick Linskey wrote:
> >> > I just committed a change that will maybe resolve the issue. Please
> >> > let us know if you see it come up again.
> >> >
> >> > I also logged the issue as OPENJPA-296.
> >> >
> >> > -Patrick
> >> >
> >> > On 7/25/07, Marc Prud'hommeaux <mprudhom@apache.org> wrote:
> >> >> Patrick-
> >> >>
> >> >> I bet you are right. Your analysis of the problem looks correct to
me.
> >> >>
> >> >>
> >> >> On Jul 25, 2007, at 9:12 AM, Patrick Linskey wrote:
> >> >>
> >> >> > Hi,
> >> >> >
> >> >> > Based on a quick read, it looks like maybe the problem is
> >> >> > UUIDGenerator.java:178. 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?
> >> >> >
> >> >> > -Patrick
> >> >> >
> >> >> > On 7/25/07, Elias Torres <elias@torrez.us> 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;
> >> >> >>
> >> >> >> }
> >> >> >>
> >> >> >> CREATE TABLE Foo (
> >> >> >>   id VARCHAR(16) NOT NULL
> >> >> >> }
> >> >> >>
> >> >> >> 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
> >> >>
> >> >>
> >> >
> >> >
> >>
> >
> >
>


-- 
Patrick Linskey
202 669 5907

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