Re: OO fans bashing Joins

From: Wolfgang Keller <wk_at_objectarchitects.de>
Date: 2000/03/06
Message-ID: <38C3F281.284B44A4_at_objectarchitects.de>#1/1

topmind_at_technologist.com wrote:

> Other OO fans seem to be saying the same thing. Is there
> a famous test that said OO is faster than Joins? Where is
> this perception coming from?

as in so many cases ... performance depends on the app you have and is not the same for every app if you take a certain db technology given.

OO using an OODB is good for apps where you need to navigate through graphs, dags, and tree structures ..

In the relational world that would mean ..

(1) looking up the next objects key
(2) going through the btree
(3) fetching the appropriate record from the disk

In OO-databases you often have clusters on pages where you load a full page from disk that pulls you (registers in an object table) a whole bunch of objects ... Like this you can get a few hundred related objects
with a single disk read if you're lucky and have no extra disk access to navigate them - only when you reach a page border you need to visit the disk again.

Faster - YES but only if the problem is the right problem for this kind of access. If clustering does not fit, it may be even slower for certain queries.
So this is good for stuff like

* CASE tools
* CAD
* any other type of check-in check-out persistence for whole object nets

that are accessed using the same form of clustering but not necessarily better for lets say processing invoices ..

if you need a few more ideas on how OODBs relate to RDBs visit my OR persistence patterns site
http://www.objectarchitects.de/ObjectArchitects/orpatterns/ Hope that clarifies a few things ..

Cheers

Wolfgang

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EMail: wk_at_objectarchitects.de
Web: http://www.objectarchitects.de/ObjectArchitects/ Received on Mon Mar 06 2000 - 00:00:00 CET