> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Dain
> Sundstrom
> Sent: Tuesday, July 24, 2001 11:44 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [JBoss-dev] ditch entity locking in favor of
> <select-for-update>
>
>
> AFAIK, file locks are new to JDK 1.4 and the behivor can vary slightly on
> different platforms.
>
> As I understand it, select for update is used to get an exclusive lock on
> the data selected for the term of the transaction. This behivor is not
> always desireable. There are certain application that don't want any
> transaction isolation. Some want for example a last commited transaction
> updates the data. This can give you huge performance boost, at
> the risk of
> data corruption, which doesn't matter in some cases.
>
I totally agree, but since JBoss already uses pessistic locking, why not
push the locking to the DB? It would greatly simplify the codebase. I
totally agree that one size does NOT fit all. Please see my "Optimisitic
Locking vs. the rest" email.
Bill
> Dain
>
> ----- Original Message -----
> From: "Bill Burke" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, July 24, 2001 9:33 AM
> Subject: RE: [JBoss-dev] ditch entity locking in favor of
> <select-for-update>
>
>
> > Why not just put a lock on the file? Same thing. I was thinking of
> > <select-for-update> more in the abstract. The CMP mechanism or the
> database
> > type-mapping could define what <select-for-update> actually meant.
> >
> > Bill
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED]]On Behalf Of
> > > Rickard Öberg
> > > Sent: Tuesday, July 24, 2001 12:45 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: [JBoss-dev] ditch entity locking in favor of
> > > <select-for-update>
> > >
> > >
> > > >The recents questions posted by James Cook got me thinking. Maybe we
> > > should
> > > >ditch the current entity locking scheme in favor of using
> > > ><select-for-update>. It would greatly simplify the entity/cache
> locking
> > > >mechanism, thus probably making it much more robust than it currently
> is.
> > > >Of course, we'd have to improve select-for-update so that it
> > > worked across
> > > a
> > > >greater range of databases and keep the old entity/cache locking for
> > > >databases that didn't. Also, what about BMP? Does the spec
> > > allow for the
> > > >container to pass on synchronization responsibities to the Bean
> > > Developer?
> > > >I'll have to check.
> > >
> > >
> > > Note that not all Entities are backed by DBMS's. In the app
> I'm working
> on
> > > currently they almost never are. Instead, I'm using XML files as
> > > the backing
> > > store, so using select-for-update is not an option.
> > >
> > > /Rickard
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > Jboss-development mailing list
> > > [EMAIL PROTECTED]
> > > http://lists.sourceforge.net/lists/listinfo/jboss-development
> > >
> >
> >
> >
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> >
>
>
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