Re: Migrate from DMT to LMT when fet$ and uet$ counts > 700,000

Charles wrote:
>
> All,
>
> I have a 1.8TB database with all Dictionary Managed Tablespaces.
>
> It's a very active SAP Business Warehouse application.
>
> We've sort of reached 'critical mass' with the fragmentation of it,
> and now SMON coalescing is so slow that "Disk Space Transaction" locks
> are hanging up the entire db.
>
> I've added events to disable SMON coalescing while we deal with this.
>
> Oracle is telling me I must run tablespace coalescing at 'quiet' times
> prior to migrating the tablespace to Locally Managed Tablespaces.
>
> I want to migrate them now to eliminate the contention on the fet$ and
> uet$ tables in the SYSTEM tablespace.
>
> I await Oracle's technical reasons why I cannot migrate now.
>
> I have done the migration in all non-production instances of this
> warehouse application; they ran seemingly ok and those databases are
> performing well, according to the warehouse users.
>
> What is your experience with this? What's the problem or the bad
> results in the LMT if I migrate these tablespaces now?
>
> Am looking for the quick fix now, to be following to reorgs later.
>
> Thank you.
>
> Charles

Basically you're damned if you do, damned if you don't.

Whilst migrating to LMT as is will leave you with a soup of extent sizes, it should still be better than where you are now.

You may want to consider

1. move to LMT
2. piecemeal moving to "nice" LMT's as HJR suggests.

Convincing management to do (b) once (a) is done might be a challenge...

C

-- 
Connor McDonald
Co-author: "Mastering Oracle PL/SQL - Practical Solutions"
ISBN: 1590592174

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