Re: performance impact of index

From: Greg Forestieri <gforestieri9_at_yahoo.com>
Date: 26 May 2004 12:31:05 -0700
Message-ID: <6a8cdd95.0405261131.e18acf5_at_posting.google.com>


"Gordon" <gordon_t_wu_at_hotmail.com> wrote in message news:<Z3nrc.289$Ny6.888_at_mencken.net.nih.gov>...
> Hi,
>
> I have a schema which is highly denormalized and purely read-only. For the
> purpose of fast data access, is there any reason not to create a bitmap
> index on every field for every table?
>
> Gordon

  1. Look into what a "data warehouse" might have to offer. Sounds like you need one.
  2. Under the category of "been there done that 20 years ago" the answer is *no*. Unless you really think someone is going to build a query where employee_address3 = &value. If it really was a good idea, Oracle would have a "build_all_columns_index" DDL command.
  3. It's entirely possible to build indexes on columns that *can never really use them* in CBO. It depends upon analysis of the data to be stored there. Simply a waste of space and can cause you to think you should RBO when in fact you should *almost* never use RBO, especially if going by raw "cost" numbers.

Greg Received on Wed May 26 2004 - 21:31:05 CEST

Original text of this message