Re: Converting from Informix to Oracle.

Hi Christopher,

I did the switch from Informix Online 7 to Oracle 7.1.6 some years ago. As far as I can remember those were the hardest parts to learn:

• physical log => rollback segments
• logical log => online redologs
• There is no utility farm like onarchive, ontape, oninit. You do *all* things through SQL, either entered into sqlplus or svrmgrl.
• A tablespace is a tablespace in both systems. Same holds for schemata.
• The online backup (without tools like rman) in Oracle is done in a "dirty" way, i. e. not in a consistent manner. In Informix you can only do as many changes as fit in the physical log whereas you can do more in Oracle (if you tried more changes these attempts would hang - not so in Oracle).
• It is a bit difficult to get a schema listing in Oracle (you have to go the detour via an empty export and import with "indexfile=abc.sql").
• In Informix we had ANSI log, unbuffered log and buffered log. In Oracle, you would always have unbuffered log.
• The optimizer is a lot more complex. This most likely has changed in the past few years.
• Reading in Informix is preventing updates of the read records by another session. In Oracle, reading data never locks another process.
• You have a lot more to configure in your startup configuration parameter file, better known as init.ora

So please bear with me as I do not have current knowledge of Informix. Anyway I hope that this information is of value to you.

Martin

christophercale_at_my-deja.com wrote:
>
> All,
>
> Our organization is comtemplating converting from Informix to Oracle
> Enterprise server. How easy will it be for me, as DBA, to crossover?
> I have 2 Informix certifications and have been doing DBA and Unix Sys
> Admin for many years. Is it going to be a big deal?
>
> Thanks,
>
> Christopher
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Wed Dec 06 2000 - 15:26:40 CST