Re: Concurrent/Parallel Execution

From: Jaap W. van Dijk <j.w.vandijk.removethis_at_hetnet.nl>
Date: Sat, 25 Nov 2006 17:07:36 GMT
Message-ID: <4568754e.3420781@news.hetnet.nl>

On Wed, 22 Nov 2006 10:23:27 -0500, "ihb" <email_at_email.com> wrote:

>Question is about Concurrent/Parallel Execution -
>
>Say data is everywhere....there are n databases (on n servers)
>In app I need to query each DB and COMBINE the results.
>
>First, is it even possible to do this (i.e. parallellism) ???
>
>Is Oracle's "Parallel Query" http://orafaq.com/faqopq.htm
>a way to achieve such concurrency.
>
>If not, then what does it take ?
>
>thanks !
>
>
>
>

Assumng you want to store the data from the sources first:

define a partitioned table with one partition for each source database.
start loading each partition from its source, do this simultaneously for all sources
use the complete table as the source for your next step.

Disadvantages:
- you cannot present the output of your selects immediately to a client program
- you have to schedule and check the finish of your concurrent processes yourself

Jaap. Received on Sat Nov 25 2006 - 11:07:36 CST