Re: Proving or Debunking the need for rebuilding

From: Richard Foote <richard.foote_at_bigpond.nospam.com>
Date: Wed, 15 Nov 2006 12:17:44 GMT
Message-ID: <IzD6h.66563$rP1.29255@news-server.bigpond.net.au>

"Mladen Gogala" <mgogala.spam-me-not_at_verizon.net> wrote in message news:pan.2006.11.15.09.18.24.305181_at_verizon.net...
> On Wed, 15 Nov 2006 07:42:37 +0000, Richard Foote wrote:
>
>> Now this could be attributed to an index rebuild but then again it might
>> not. For example, I assume you re-analyze the index after the rebuild ?
>> What
>> are the differences in index statistics before/after the rebuild ? When
>> was
>> the index last analyzed prior to the rebuild ? There was one classic
>> thread
>> here a while ago where Mike Ault swore an index rebuild changed the
>> clustering factor of an index only to realize (eventually and somewhat
>> painfully) that the rebuild made no difference to the CF, it was simply
>> the
>> statistics being no longer fully up to date. Is it possible that by
>> simply
>> re-analyzing the index/table, performance improves without the need for
>> the
>> rebuild ? I've seen this on various occasions ...
>
> There is also a classic presentation about indexes on OAUG now moved
> to Miracleas.dk:
> http://www.miracleas.dk/images/upload/Docs/Richard%20Foote.pdf
> I find the myth debunking section hilarious. That presentation explained
> CF to me long before Jonathan's book.
>

Hi Mladen

Hey, I think I've seen that presentation somewhere before ...

Must read it one day ;)

Cheers

Richard Received on Wed Nov 15 2006 - 06:17:44 CST