undo management

[Mnemonical]

I'm into 9i, but my company has some other apps with 8.1.7 and I have to take care of it. I was looking for undo_management = auto for 8i but I see it's available in 9i or later ... although there's LMT in 8.1.7

So, only user tablespaces can be LMT, I have to use those old rollback segments and setting storage parameters for segments because there's no space segment management = auto?!!

yuuk.


F

[SANJAY_G]

"Auto Undo Management" and "Auto Space Segment Management" is available in 9i BUT you can have LMT for SYSTEM and RBS even in 8i.

[Mnemonical]

let's say I'm in 8.1.7 and all tablespaces, including system, temp, rbs ... all of them are locally managed. Am I right if I say that I don't need to set segment storage parameters, like initial, next, pctused and optimal (for rollback segments) ... ?!! In other words, a locally managed rollback segment is almost like a almost-more-or-less-undo-tablespace?


F

[mike2000]

WRONG

[Mnemonical]

If it's wrong why should I use locally managed tablespaces in 8.1.7 then?!!! If I use locally managed tablespaces I have the following advantage, second Oracle doc: "The storage parameters NEXT, PCTINCREASE, MINEXTENTS, MAXEXTENTS, and DEFAULT STORAGE are not valid for locally managed tablespaces".






F

[jmodic]

Originally posted by Mnemonical
If it's wrong why should I use locally managed tablespaces in 8.1.7 then?!!! If I use locally managed tablespaces I have the following advantage, second Oracle doc: "The storage parameters NEXT, PCTINCREASE, MINEXTENTS, MAXEXTENTS, and DEFAULT STORAGE are not valid for locally managed tablespaces".

If this is the only "advantage" about LMT over DMT you could figured out from the manuals, then perhaps you realy shouldn't use LMTs...

[Mnemonical]

Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Who said I said "the only advantage"?
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Read again. I said if I use locally managed tablespaces why should I set storage parameters for rollback segs? It's not of my interests if LMT is better or worst than DMT ...



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[jmodic]

Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

Didn't your reply started with:
"If it's wrong why should I use locally managed tablespaces in 8.1.7 then?!!!"?

Your assumptions from previous message were not correct: "In other words, a locally managed rollback segment is almost like a almost-more-or-less-undo-tablespace?", and you've got the right answer. Nothing could be further from truth than your above assumption. RBS in LMT is totaly totaly totaly different than undo tablespaces as in 9i. Totaly different concept, totaly different technology, totaly different behavior.

And I can't understand your wories about setting the storage parameters for rollback segments in LMT (and BTW, some of the storage parameters *are* allowed in LMT). What difference does it make? How often do you create rollback segments? More or less once in a liftime of a database, I guess. And after all, why don't you try it on some test instance and see what the results will be?

[Mnemonical]

If I use locally managed tablespaces, why should I set storage parameters for rollback segs?





F

[SANJAY_G]

Originally posted by Mnemonical
If I use locally managed tablespaces, why should I set storage parameters for rollback segs?





F

Because "Locally Managed RBS Tablespace" and "Automatic Undo Management" are two different concepts.
Creating your rollback tablespace as LMT doesn't mean that you are using AUM. You still need to create rollback segments even you are using LMT. But if you are using AUM you just create a UNDO tablespace. Set UNDO_MANAGEMENT, UNDO_RETENTION and you are done. You do not need to create any rollback segments.