Re: Indexed Tablespace Fragmentation

Niall Litchfield <n-litchfield_at_audit-commission.gov.uk> wrote:
>You will need to do this on a regular basis if you don't use LMT's. My
>suggestion would be that LMT is suitable for you if your indexes are within
>an order of magnitude of each other in size. you don't care if you have 1000
>extents though you might if you had 10000.

I'm becoming increasingly suspicious that LMTs become less efficient than DMTs for very large numbers of extents, i.e of the order 100,000 extents. Symptoms are that HW enqueues take much longer, I'd guess Oracle has to trawl through the bitmaps sequentially instead of following a B*Tree.

One obvious answer is Don't Do That Then. However, sometimes the developers forget to mention a table...

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/