Re: LMT with autoallocate

Comments embedded

Hth,

Sybrand Bakker, Oracle DBA

"Vikas Agnihotri" <onlyforposting_at_yahoo.com> wrote in message news:77e87b58.0105220927.432b49d8_at_posting.google.com...
> Since HJR doesnt have first-hand experience with autoallocate LMTs, I
> wanted to check if these beasts are used in real-world production
> databases at all.

Yes they are

>
> Could someone who has used LMT (locally managed tablespaces) with
> either autoallocate or uniform extents comment on their alleged
> performance benefits, administrative issues, etc?

Obviously, an enormous reduction of selects on fet$ and uet$ in system (where dictionary managed tablespaces have their repository)

In 8.1.6 however on Solaris there is a problem with exporting uniform LMTs: this will result in EXP-0068. The data is exported though. Autoallocate doesn't have this problem.

>
> Would you recommend LMT over dictionary managed?

Yes

If so, would you
> recommend uniform or autoallocate?
>

autoallocate. There is a very good discussion on this in Jonathan Lewis book Practical Oracle 8i
Having extents bigger than can be read with 1 I/O request is according to him more or less useless.
Oracle decides on whether it will use 64k or 1 M extents depending on O/S, so you just shouldn't bother as long as you use maxextents unlimited.

> Thanks...
Received on Tue May 22 2001 - 14:21:43 CDT