Re: local managed ts (indizes)

"mkoster" <member14794_at_dbforums.com> wrote in message news:2724210.1049368080_at_dbforums.com...
>
> hi,
>
> oracle 8.1.7
> aix 4.3.3 rs/6000
>
> on my testserver i have rebuild the indizes in an local-managed
> tablespace.
> this shrink the tablespace from 6,7 gb to 3,7 gb.
>
> what do vou mean about the performance, can i count on a better
> performance ???

see http://www.dbazine.com/jlewis8.html for a thorough discussion.

One thing that has occurred to me that *may* result in better performance and that I haven't seen discussed elsewhere is to do with extent sizes. In general it makes sense to pick extent sizes that are equal to n*multiblock read count where n is an integer. Choosing to use uniform extent sizes means that you can enforce this rather than have odd extra reads here and there when scanning the objects in the tablespace. However as with the other performance benefits (that I as well as others have probably overstated in the past) this is an indirect effect of choosing to use an LMT and should in most cases be minimal.

I haven't quantified this but I would be surprised if overall a well configured LMT database outperformed a well configured DMT database by more than say 5-10%. I'd be amazed if end-users noticed performance improvements of less than 50% by contrast. The advantages lie mainly in ease of administration and in avoiding costly reorganisations.

--
Niall Litchfield
Oracle DBA
Audit Commission UK