Re: Databases and Instances

On Fri, 31 Mar 2000 15:24:08 +0200, Stefan Jahnke <q5665841_at_bonsai.fernuni-hagen.de> wrote:

>So, after all the replies, I think it's just different concepts.

Exactly.

>logically seperate data for several applications etc. The only
>disadvantage I see here is, that you only have one SGA and it might be
>problematically to tune one instance for different demands. After all,
>the thing to do would be: Build seperate instances or, at least for
>production, even put completely seperated installations on physically
>seperated machines.

Yes. ORACLE is (finally!!!!) starting to do something about allowing proper partitioning of the shared bits in an instance. It will get better, but it's a weak point now. "Databases" of different performance characteristics are still hard to tune in a single instance. Sometimes just about impossible. So, multiple instances and/or multiple nodes.

>Of course, you encounter the same problem when you
>have 2 or more databases within one DB2 instance.

I thought that was one of the strong points in DB2. They can have better control over this in mainframes than ORACLE in UNIX or NT. With UNIX and smaller boxes, I dunno if it's possible to do without major code changes to the database engine itself.

>Actually, I think it's funny how people start throwing mud at each other
>when it comes up to "what database is the best......".

Correction: the Sybase and sql server loosers throw the mud. Little wonder they get some back too. Rarely do you see any "ORACLE-head" taking the initiative in these matches.

It's a fact that ORACLE stuck to the SQL model all along, like Informix and DB2. The other two had "fake" SQL for years. It's only in the last few they have improved that part of their proprietary approach. About bloody time...

>By the way, does somebody really have a proof on how good or bad
>informix, sybase (or sql server, but that's the same code-base anyway
>:-) or others compare to oracle or db2 when it comes to things like
>perfomance,

about par in most cases. In future, I expect sql server to be the nearest. If nothing else because it benefits from a proprietary environment which can be tweaked to aid its performance. They are already doing it, remains to be seen if the market will wear another round of proprietary stuff. Been tried before, didn't work.

>scalability

Informix. The others just fudge things to look "scalable". I think Informix might be the honourable exception of this lot. Unfortunately, there is a perception in the market that Informix is "gone". Nothing could be more wrong.

>and how stable are they ?

That's a hard one. Abstracting from external influences such as OS stability and such, I'd say Informix might be right up there with ORACLE and DB2. Their "embedded engine" is pretty solid and widely used by "turn-key solution" developers. And they have a very solid implementation of SQL.

Cheers
Nuno Souto
nsouto_at_nsw.bigpond.net.au.nospam
http://www.users.bigpond.net.au/the_Den/index.html Received on Fri Mar 31 2000 - 00:00:00 CST