correct sequence manager with MSSqlServer and Weblogic

[Bonnie MacKellar <BM...@mobius.com>]

We are trying to run OJB with MSSqlServer and Weblogic. We are NOT
using EJBs, however, just JNDI DataSources.

After seeing the post earlier today about not using the High/Low sequence
manager
implementation with datasources, I went to the documentation, and sure
enough, it
does say that. I missed it earlier. Unfortunately, I have been using it.
It looks like the database-based implementations are out because we are
using
MSSqlServer. So that leaves the in-memory sequence manager. The
documentation
just says not to use in a clustered environment. Does anyone know if it is
safe with managed datasources? Or does it have problems like the High/Low
manager? By the way, our database will not be updated by other applications.

thanks,
Bonnie MacKellar
software engineer
Mobius Management Systems, Inc.
bmackell@mobius.com

Re: correct sequence manager with MSSqlServer and Weblogic

[Armin Waibel <ar...@code-au-lait.de>]

Hi Bonnie,

> We are trying to run OJB with MSSqlServer and Weblogic. We are NOT
> using EJBs, however, just JNDI DataSources.
>
> After seeing the post earlier today about not using the High/Low
sequence
> manager
> implementation with datasources, I went to the documentation, and sure
> enough, it
> does say that. I missed it earlier. Unfortunately, I have been using
it.
> It looks like the database-based implementations are out because we
are
> using
> MSSqlServer. So that leaves the in-memory sequence manager. The
> documentation
> just says not to use in a clustered environment. Does anyone know if
it is
> safe with managed datasources? Or does it have problems like the
High/Low
> manager? By the way, our database will not be updated by other
applications.

Should be safe in your case (and definitely the best performing
solution).
The in-memory implementation is 'nearly independent' from the
database. Only the first time an UID is needed, in the associated
db-table the max id of the PK-column was calculated using a
db-select. All following UID calls only increment the calculated
value.

Using MSSQL you could use another alternative implementation,
please see

http://db.apache.org/ojb/sequencemanager.html#Oracle-style sequencing

But I think in your specific case the in-memory implementation
is the best solution.

regards,
Armin

>
> thanks,
> Bonnie MacKellar
> software engineer
> Mobius Management Systems, Inc.
> bmackell@mobius.com
>
>