RE: DB2 to Oracle migration

  • From: "Justin Cave (DDBC)" <jcave@xxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 12 Mar 2004 10:32:29 -0700

 
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@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Birkir Bjornsson
Sent: Friday, March 12, 2004 4:52 AM
To: oracle-l@xxxxxxxxxxxxx
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 I´m slowly coming to that 
conclusion that the easiest way is either to use ASCII files or Heterogenous 
Services, I´ve 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@xxxxxxxxxxxxx 
>[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Birkir Bjornsson
>Sent: Wednesday, March 10, 2004 4:49 PM
>To: oracle-l@xxxxxxxxxxxxx
>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@xxxxxxxxxxxxx 
>>[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Birkir Bjornsson
>>Sent: Wednesday, March 10, 2004 7:40 AM
>>To: oracle-l@xxxxxxxxxxxxx
>>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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