"Dusan Bolek" <pagesflames_at_usa.net> wrote in message
news:1e8276d6.0207022257.445e12b7_at_posting.google.com...
> "Howard J. Rogers" <dba_at_hjrdba.com> wrote in message
news:<aft2jm$ahm$1_at_lust.ihug.co.nz>...
> > If you do the conversion, remember to create a range of extent-sized
> > tablespaces (64K, 512K, 1M, 8M, 64M), and move the right table(s) into
the
> > right tablespace.
>
> I haven't fully confidence in this. When I have begun to use LMTs I
> did some tests. I've measured performance while using different
> extent-sized. I've learned that even with 8k extent size and 300MB
> object the performance difference against 512k extent size was just
> few percent.
> So I have decided to use uniform extent size 64K for *ALL* objects in
> our databases. The biggest tables has about 500 - 700 MB. My idea is
> to has only as few tablespaces as needed, because of administration
> overhead.
Jonathan pointed out earlier (if I read him correctly) that there is a 'per
tablespace' limit for the number of extents which will fit in the bitmap. So
you may not get degradation on any individual table with a few thousand
extents but if the bitmap is dealing with hundreds of thousands of extents
it may suffer.
--
Niall Litchfield
Oracle DBA
Audit Commission UK
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Received on Wed Jul 03 2002 - 03:40:24 CDT
