On Fri, Oct 11, 2002 at 08:46:58AM +0200, Jon Haugsand wrote:
> * Marius Kotsbak
> > > > >for (id=0;id++;id<1000) {
> > > > > // Start transaction
> > > > > Collection c=findByStatus(id,status);
> > > > > for(i=c.iterator();i.hasNext();) {
> > > > > ((EntityLocal) (i.next())) . setStatus(newStatus);
> > > > > }
> > > > > // End transaction
> > > > >}
> > > > >
> > > > Why not package the whole in one transaction (including the outher
> > > > for-statement), too see if this speeds things up, if it doesn't change
> > > > the semantics of your operation. Or you might start a nested
> > > > transaction for the inner for.
> > >
> > > We can try this in order to see the effect, but we cannot change this
> > > permanently.
> > Why not?
>
> Several reasons:
>
> 1. The transaction will take too long time, locking other requests
> out.
> 2. An exception would roll back all updates to the entity bean
> instances.
>
> Of course, no 2 can be solved by designing differently, but that is
> also a risk in our project. No 1 has to be tested.
In this case, I miss the sql-statement
"UPDATE sometable SET status=2 WHERE status=6"
which I don't think EJB/JBoss-QL can handle. This will probably speeds things up
considerably.
If it is an unsolvable problem, a hack would be to use a sql like that directly to the
DB. You might then perhaps not use all commit options in jboss safely though (but I
think the default for EJB2.x beans handles this).
You might also optimize a bit by tweaking in jbosscmp-jdbc to fetch multiple entites
at a time, and have the status as one load group.
>
> --
> Jon Haugsand, <[EMAIL PROTECTED]>
> Norges Bank, <http://www.norges-bank.no>
>
>
>
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--
MVH
Marius Kotsbak
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