Re: Multi-User Issue

[Roy Ladner <rladner@nrlssc.navy.mil>]

I haven't noticed other problems.  The duplicate ID problem comes up when
Ozone.LocalDatabase is instanced by two different threads in different VMs.  If
multiple threads have references to a single instance of Ozone.LocalDatabase
then IDs do not appear to be duplicated.

Does anyone know of any high level description of Ozone's transaction management
scheme?  That may make it a bit easier to figure out what's going on.

Reason wrote:

> I haven't had the chance to check on this due to a hectic work schedule, but
> it's definitely something I'll be looking at in the near future -- some of
> my software in progress counts on the uniqueness of those IDs, and I'll have
> to implement my own unique number generator if the IDs aren't unique for
> heavy thread usage.
>
> Does it show any other signs of flakiness while you're getting duplicate
> IDs, such as losing objects?
>
> Reason
> http://www.exratio.com/
>
> ----- Original Message -----
> From: "Roy Ladner" <rladner@nrlssc.navy.mil>
> To: <ozone-users@ozone-db.org>
> Sent: Monday, April 23, 2001 12:46 PM
> Subject: Multi-User Issue
>
> > With more than one user accessing an Ozone repository (each in a
> > separate thread with it's own instance of LocalDatabase), I have noticed
> > that Ozone assigns the same id to the object created by each user when
> > each calls db.createObject(class).  This happens when both calls to
> > createObject occur before either user calls db.close().  Am I
> > overlooking something or does Ozone not protect against this?
> >
> > Dr. Roy Ladner
> > Naval Research Laboratory