Re: experience with convert Dictionary managed tbs to LMT with dbms_space_admin

On 07/01/2005 05:19:31 AM, zhu chao wrote:
> Hi, Lex,
> Rebuild would be nice but as I said before, our database is pretty
> big (1TB-3TB)

Nice range of values. Your database can be 1TB but can also be 3 times as big.

> and it is impossible to rebuild it without days's
> downtime.

Actually, migration is usually much faster. Depending on your hardware, 2 hours sounds pretty close.

> The maximum downtime is 2 hours for us. So we have to live
> with current.

No you don't. Test migration on the same platform, calculate the necessary time, and, if it exceeds 2 hours, create standby which will be open read only and will keep the query part of the application working for an additional hour, if need be. Where is will, there is a way.

>
> ZimSbait, the thing you mentioned is critical for production box. I
> am not sure what you was your exact problem. I don't have much
> experience with the converted local managed tablespace, according to
> metalink, it use the same extent management policy as dictionary
> managed tablespace, so what is the difference?

The difference is that LMT usis multiples of few binary extent sizes. LMT, by its nature can't have all kinds of extents like dictionary tablespaces were able to.

-- 
Mladen Gogala
Oracle DBA


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