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RE: DB2 to Oracle migration

From: Justin Cave (DDBC) <jcave_at_ddbcinc.com>
Date: Fri, 12 Mar 2004 10:32:29 -0700
Message-ID: <87E9F113CEF1D211A4C3009027301874195D45@ddbcinc.ddbc.local>

 

Heterogeneous Services certainly isn't the easiest product in the world to set up and configure, particularly your first time. I seem to recall that my first time took me the better part of a weekend, but the installation process has been improved a bit since then.

If your downtime window is such that text files will let you migrate the data in time, that's likely the option that will involve the least work on your side. If your downtime window is such that you can't afford multiple copies of data, Heterogeneous Services is your best bet. Compared to the time you'll probably be spending writing the transformation and loading logic, configuring Heterogeneous Services probably isn't too huge an investment.

Justin Cave
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Birkir Bjornsson Sent: Friday, March 12, 2004 4:52 AM
To: oracle-l_at_freelists.org
Subject: Re: DB2 to Oracle migration

Hi Justin

The schemas are totally different. So it looks like the migration tools are not going to help me. I will be selecting from a few tables in DB2 and inserting that into one table in Oracle for example. So Im slowly coming to that conclusion that the easiest way is either to use ASCII files or Heterogenous Services, Ive never used them. Is it very complicated to set it up?

Justin Cave (DDBC) wrote:

>How much data are you talking about moving? What sort of window do you have to move the data? I'm assuming that you will be shutting down the DB2 database, migrating the data, and then bringing up the Oracle database-- how long can the system be unavailable?
>
>How close are the two schemas structurally? If they are radically different, Migration Workbench is probably a bad idea.
>
>ASCII files are a good option, but that will involve writing all the data to disk, copying it around the network, loading it into the database, and manipulating the data into the new schema. That's a lot of copying if there is a lot of data or a small window. You may be able to move more data more quickly if you set up Heterogeneous Services and create a database link to the DB2 database from Oracle-- that would also let you do the transformation processing in parallel. From a setup and configuration perspective, however, this will be more work than text file extracts.
>
>Justin Cave
>Distributed Database Consulting, Inc.
>http://www.ddbcinc.com/askDDBC
>
>-----Original Message-----
>From: oracle-l-bounce_at_freelists.org
>[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Birkir Bjornsson
>Sent: Wednesday, March 10, 2004 4:49 PM
>To: oracle-l_at_freelists.org
>Subject: Re: DB2 to Oracle migration
>
>Hi Justin
>Thanks for your response. Well Im migrating the database only once. The
>thing is that I have to extract the data from DB2 to an already made
>schema in Oracle.
>So could I use Oracle Migration Workbench, or should I just make an
>ASCI file with the data from DB2 and use SQLLoader to insert it to Oracle.
>What would you
>say is the easiest way? Or do you have some other hint for me?
>
>Thanks in advance
>
>Kind Regards
>-Bippi
>
>Justin Cave (DDBC) wrote:
>
>
>
>>Is the question about a one-time migration, i.e. moving an application that is currently accessing DB2 to access Oracle, in which case the Oracle Migration Workbench is probably a good first step? Or is the question about regularly migrating data from DB2 to Oracle, i.e. replication, in which case Heterogeneous Connectivity would be a good approach?
>>
>>If the question is the former-- a complete move from one database to another-- be aware that you will probably have to invest a significant amount of time after the Migration Workbench moves the code to Oracle to get equivalent performance from Oracle. In general, applications are going to do things that work really well in one database but that aren't appropriate in another database. Migration Workbench will do a relatively dumb conversion of the code, which is fine for 60% of the cases, but you'll have to manually fix up the other 40%.
>>
>>Justin Cave
>>Distributed Database Consulting, Inc.
>>http://www.ddbcinc.com/askDDBC
>>
>>-----Original Message-----
>>From: oracle-l-bounce_at_freelists.org
>>[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Birkir Bjornsson
>>Sent: Wednesday, March 10, 2004 7:40 AM
>>To: oracle-l_at_freelists.org
>>Subject: DB2 to Oracle migration
>>
>>Hi
>>
>>I have to migrate a DB2 database to Oracle and was wondering if any of
>>you have ever done it and have some hints for me.
>>
>>
>>Thanks in advance
>>Bippi
>>
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Received on Fri Mar 12 2004 - 11:26:33 CST

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