Hello there,

We're using Baan IVc2 with Oracle 8.1.7 on a Solaris 8 server and I'm asking myself if it is a good idea to migrate my tablespaces from dictionary to locally managed. From Oracle point of view it a great deal but, what consideration do I have to see from the Baan side? How can any future table reorganization can be affected, since the ora_storage file seems not to be necesary, because Oracle itself will take care of the objects?

I would like somebody bring me some ligths to this matters, to have more strongs arguments to migrate from DMT to LMT.

Any sugestion, comments, experiences will be highly apreciated.

Thanks in advance!!

Eric

Oracle LMT in Oracle 8i is a bad thing in my opinion. I've seen multiple instances of poor performance after that type of migration. It seems that Oracle got the kinks worked out in Oracle 9i.

As far as LMT vs DMT with Baan.. I've found that with 9i it really works well, especially if you use LMT with uniform extent size. Then you setup multiple tablespaces (DATSMALL/DATMED/DATLARGE/DATXLARGE,etc) this takes a lot of work to segregate your tables that way, but In the end it leaves you with very little management needed.

The ora_storage isn't quiet worthless at this point. (Of course you're telling which tablespace to go to, but there's more... ) One thing I found when playing with LMT is that if you DO specify a storage clause Oracle will create enough extents to handle it.. For example, if you have table tiitm001 in tablespace DATMED (extent size 8k), and your storage clause is (initial 20k) when you do a "create table" in Baan Oracle will allocate 3 uniform extents to handle the data

An additional perk of LMT is that if you're rebuilding your companies (migrating prod to test, etc) often, then your system tablespace doesn't get all chunked up

Dave

Thank you Dave,

I apreciate your comments. Unfurtunatelly we're not expecting to migrate to Oracle 9i until 2 years has passed, so we can use this feature completly. Until that happens, I have to find the best way to manage my speces and I think that LMT could help.

Thanks agin,

Eric

Ok... but when the performance problems start poping up.. don't come crying to me :)

I agree with Dave: Skip LMT, if you run O8i.

I somehow do not believe, it will take you two years to go to Oracle9i.
If I am not mistaken, than Oracle8i will be desupported on most (all?) platforms by the end of the year. If SSA get their grips together, then they will act like SAP and stop supporting their own product, if it is not run on a supported platform combination.

So most likely sooner, then you think, O9i is coming.

Enjoy anyway

Markus

Hello Markus,

Thanks a lot for your recomendation. Upgrading to Oracle 9i is what I really wish and recomend here, but in this side of the world things works little different. All in all, I'll do my job and start to investigate for a possible migration.

I'll let the LMT for later.

Thanks again Markus and Dave.

Greetings!


I agree with Dave: Skip LMT, if you run O8i.

I somehow do not believe, it will take you two years to go to Oracle9i.
If I am not mistaken, than Oracle8i will be desupported on most (all?) platforms by the end of the year. If SSA get their grips together, then they will act like SAP and stop supporting their own product, if it is not run on a supported platform combination.

So most likely sooner, then you think, O9i is coming.

Enjoy anyway

Markus

I totally disagree,

we migrated to LMT about a year ago, and we dídn´t detect any performance decrease at all - far from it - performance got a little bit better

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Michael

Hi Michael,

your experience might very well be true, but

a) Not all customers hit all existing (performance related) bugs

b) Can you be sure, that not some other parameters were changed?

c) Often in a migration like this, the benefit does not result from the change of technology, but from some side effect, like reorganizing your DB during the exp/imp involved.


It is always difficult to generalize statements like "LMT does not perform in O8". we should be carefull doing this. But most likely a statement like "Quite a few O8i implementations faced performance problems with LMT" is true.

Regards

Markus

Hello Markus,

I want to strictly advice you to use LMT. After reorganising your tables it makes only a little difference, but the longer you´ll work the more important become the difference. The risk of row migration and row chaining is getting lower.
Even you don´t need to waste your time in modifiying yout ora_storage files.
It is possible to use LMT with Oracle 8.1.7 but the implementation in Oracle 9iR2 is better.
Because of the performance enhancements and the new features I would use Oracle 10g instead.
Most of the general performance issues based on a bad database installation.


Best regards

:D

That is a good point, but I think a well managed 8i DMT will perform better than a well managed 8i LMT. Well managed meaning taking care of chained/migrated rows and making sure to set your parameters correctly to avoid them.. and of course, the DBAs joy of reorging the tables every once in a while...

Dave