Hi elephantwalker,
A big thanks for the help. This is a great support from
elephantwalker with quick replies.God bless.
thanks,
Prasanth.
>From: "The elephantwalker" <[EMAIL PROTECTED]>
>Reply-To: Orion-Interest <[EMAIL PROTECTED]>
>To: Orion-Interest <[EMAIL PROTECTED]>
>Subject: RE: CMP 2.0 vs BMP - Which performes better?
>Date: Fri, 5 Apr 2002 11:54:00 -0800
>
>See my earlier post on this thread. You can use custom finders with
>_extreme_ ease in Orion. I gave an example for Oracle (since Oracle does
>not
>_have_ the sql LIMIT statement). For other databases, you could use a LIMIT
>statement in your custom finder.
>
>Regards,
>
>the elephantwalker
>www.elephantwalker.com
>
>
>-----Original Message-----
>From: [EMAIL PROTECTED]
>[mailto:[EMAIL PROTECTED]]On Behalf Of prasanth sb
>Sent: Friday, April 05, 2002 7:20 AM
>To: Orion-Interest
>Subject: RE: CMP 2.0 vs BMP - Which performes better?
>
>
>Hi Jeff and other dear friends,
> I had this doubt in my mind very earlier.
>When we load very large amount of data from the database, how it can be
>handled? If we use result sets and iterate, this is going to take a long
>time? How can we limit the number of records that is present
>in the memory at a time?
>
>thanks,
>Prasanth.
>
>
>
>
>
> >From: "Jeff Schnitzer" <[EMAIL PROTECTED]>
> >Reply-To: Orion-Interest <[EMAIL PROTECTED]>
> >To: Orion-Interest <[EMAIL PROTECTED]>
> >Subject: RE: CMP 2.0 vs BMP - Which performes better?
> >Date: Thu, 4 Apr 2002 16:22:17 -0800
> >
> > > From: Curt Smith [mailto:[EMAIL PROTECTED]]
> > >
> > > > There are several constraints to BMP beans which make them almost
> >always
> > > > perform slower than CMP beans. In particular, the inability to bulk
> > > > load beans from finder methods is a nearly fatal defect.
> > >
> > > I'd like to know more of the details?
> > >
> > > How does the container deal with the following finder in CMP
> > > differently than BMP?
> > >
> > > Collection remoteRefs = home.findSalaryGreaterThan ( "50,000");
> >
> >Lets assume this produces 1000 results which you then iterate through.
> >
> >With BMP beans, this will require 1001 database queries. First the
> >finder, then 1000 selects to load each bean.
> >
> >With CMP, it's actually rather ambiguous what will happen. Last time I
> >checked, Orion will load all the beans into an ArrayList. Yes, lots of
> >memory consumed, but a *lot* better than 1001 database hits. Admittedly
> >a bigger problem with orders of magnitude more objects, but even with
> >BMP you're going to choke if the finder query returns a billion rows of
> >primary key data.
> >
> >Some containers (not Orion, I don't think) allow you to specify that
> >finders should lazy-load beans. But this brings you back to BMP
> >performance. Some containers allow you to define "field groups" to
> >minimize the amount of data brought back (especially useful if you store
> >blobs), but not Orion.
> >
> >Personally, I don't understand why containers don't implement
> >Collections backed by the ResultSet directly. 98% of the time, the
> >client just creates an iterator and walks the results. If the client
> >does something that the ResultSet can't support, build the full
> >Collection.
> >
> >Jeff Schnitzer
> >[EMAIL PROTECTED]
> >
>
>
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