Re: Low cardinality,high concurrent in OLTP, how to improve query performance?

From: Michael Austin <maustin_at_firstdbasource.com>
Date: Mon, 02 Feb 2009 22:16:11 -0600
Message-ID: <eAPhl.15933$yr3.8096_at_nlpi068.nbdc.sbc.com>

Mladen Gogala wrote:
> On Sat, 31 Jan 2009 17:44:03 -0600, Michael Austin wrote:
>

>> I know of no reason to not create an index on this column. Yes it is can >> produce a somewhat lop-sided BTree but, it will prevent a FTS.

Restated: this has, in the past, helped to prevent FTS in some of the instances where this method was used on databases I have managed.

which is why you stated "Not necessarily".

>
> Not necessarily. In the beginning, and my impression is that the
> application is only being developed, there will be significant
> portion of the daily data in the table. Full table scan is more
> than likely, regardless of the index. Preventing full table scan
> may not be such a good idea, because searching through the large
> quantity of data using index scans is much slower than doing it by
> the full table scan.
>
>
>
Received on Mon Feb 02 2009 - 22:16:11 CST